1
|
Lee N, Kim S, Lee NY, Jo H, Jeong P, Pagire HS, Pagire SH, Ahn JH, Jin MS, Park CS. Activation mechanism and novel binding sites of the BK Ca channel activator CTIBD. Life Sci Alliance 2024; 7:e202402621. [PMID: 39089879 PMCID: PMC11294680 DOI: 10.26508/lsa.202402621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 07/12/2024] [Accepted: 07/15/2024] [Indexed: 08/04/2024] Open
Abstract
The large-conductance calcium-activated potassium (BKCa) channel, which is crucial for urinary bladder smooth muscle relaxation, is a potential target for overactive bladder treatment. Our prior work unveiled CTIBD as a promising BKCa channel activator, altering V 1/2 and G max This study investigates CTIBD's activation mechanism, revealing its independence from the Ca2+ and membrane voltage sensing of the BKCa channel. Cryo-electron microscopy disclosed that two CTIBD molecules bind to hydrophobic regions on the extracellular side of the lipid bilayer. Key residues (W22, W203, and F266) are important for CTIBD binding, and their replacement with alanine reduces CTIBD-mediated channel activation. The triple-mutant (W22A/W203A/F266A) channel showed the smallest V 1/2 shift with a minimal impact on activation and deactivation kinetics by CTIBD. At the single-channel level, CTIBD treatment was much less effective at increasing P o in the triple mutant, mainly because of a drastically increased dissociation rate compared with the WT. These findings highlight CTIBD's mechanism, offering crucial insights for developing small-molecule treatments for BKCa-related pathophysiological conditions.
Collapse
Affiliation(s)
- Narasaem Lee
- https://ror.org/024kbgz78 School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
| | - Subin Kim
- https://ror.org/024kbgz78 School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
| | - Na Young Lee
- https://ror.org/024kbgz78 School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
| | - Heeji Jo
- https://ror.org/024kbgz78 School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
| | | | - Haushabhau S Pagire
- https://ror.org/024kbgz78 Department of Chemistry, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
| | - Suvarna H Pagire
- https://ror.org/024kbgz78 Department of Chemistry, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
| | - Jin Hee Ahn
- https://ror.org/024kbgz78 Department of Chemistry, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
| | - Mi Sun Jin
- https://ror.org/024kbgz78 School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
| | - Chul-Seung Park
- https://ror.org/024kbgz78 School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
| |
Collapse
|
2
|
Megaw R, Moye A, Zhang Z, Newton F, McPhie F, Murphy LC, McKie L, He F, Jungnickel MK, von Kriegsheim A, Tennant PA, Brotherton C, Gurniak C, Gross AK, Machesky LM, Wensel TG, Mill P. Ciliary tip actin dynamics regulate photoreceptor outer segment integrity. Nat Commun 2024; 15:4316. [PMID: 38773095 PMCID: PMC11109262 DOI: 10.1038/s41467-024-48639-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 05/09/2024] [Indexed: 05/23/2024] Open
Abstract
As signalling organelles, cilia regulate their G protein-coupled receptor content by ectocytosis, a process requiring localised actin dynamics to alter membrane shape. Photoreceptor outer segments comprise an expanse of folded membranes (discs) at the tip of highly-specialised connecting cilia, into which photosensitive GPCRs are concentrated. Discs are shed and remade daily. Defects in this process, due to mutations, cause retinitis pigmentosa (RP). Whilst fundamental for vision, the mechanism of photoreceptor disc generation is poorly understood. Here, we show membrane deformation required for disc genesis is driven by dynamic actin changes in a process akin to ectocytosis. We show RPGR, a leading RP gene, regulates actin-binding protein activity central to this process. Actin dynamics, required for disc formation, are perturbed in Rpgr mouse models, leading to aborted membrane shedding as ectosome-like vesicles, photoreceptor death and visual loss. Actin manipulation partially rescues this, suggesting the pathway could be targeted therapeutically. These findings help define how actin-mediated dynamics control outer segment turnover.
Collapse
Affiliation(s)
- Roly Megaw
- MRC Human Genetics Unit, MRC Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK.
- Princess Alexandra Eye Pavilion, NHS Lothian, Edinburgh, EH3 9HA, UK.
| | - Abigail Moye
- Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Zhixian Zhang
- Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Fay Newton
- MRC Human Genetics Unit, MRC Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK
| | - Fraser McPhie
- MRC Human Genetics Unit, MRC Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK
| | - Laura C Murphy
- MRC Human Genetics Unit, MRC Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK
| | - Lisa McKie
- MRC Human Genetics Unit, MRC Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK
| | - Feng He
- Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Melissa K Jungnickel
- MRC Human Genetics Unit, MRC Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK
| | - Alex von Kriegsheim
- Edinburgh Cancer Research United Kingdom Centre, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Peter A Tennant
- MRC Human Genetics Unit, MRC Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK
| | - Chloe Brotherton
- MRC Human Genetics Unit, MRC Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK
| | - Christine Gurniak
- Institute fur Genetik, Universitat Bonn, Karlrobert-Kreiten-Strasse, 53115, Bonn, Germany
| | - Alecia K Gross
- University of Alabama at Birmingham, 2nd Ave South, Birmingham, AL, 35294, USA
| | - Laura M Machesky
- CRUK Scotland Institute, Switchback Road, Bearsden, Glasgow, G61 1BD, UK
- Department of Biochemistry, University of Cambridge, Cambridge, CB1 7UY, UK
| | - Theodore G Wensel
- Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Pleasantine Mill
- MRC Human Genetics Unit, MRC Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK
| |
Collapse
|
3
|
Cebi E, Lee J, Subramani VK, Bak N, Oh C, Kim KK. Cryo-electron microscopy-based drug design. Front Mol Biosci 2024; 11:1342179. [PMID: 38501110 PMCID: PMC10945328 DOI: 10.3389/fmolb.2024.1342179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 01/31/2024] [Indexed: 03/20/2024] Open
Abstract
Structure-based drug design (SBDD) has gained popularity owing to its ability to develop more potent drugs compared to conventional drug-discovery methods. The success of SBDD relies heavily on obtaining the three-dimensional structures of drug targets. X-ray crystallography is the primary method used for solving structures and aiding the SBDD workflow; however, it is not suitable for all targets. With the resolution revolution, enabling routine high-resolution reconstruction of structures, cryogenic electron microscopy (cryo-EM) has emerged as a promising alternative and has attracted increasing attention in SBDD. Cryo-EM offers various advantages over X-ray crystallography and can potentially replace X-ray crystallography in SBDD. To fully utilize cryo-EM in drug discovery, understanding the strengths and weaknesses of this technique and noting the key advancements in the field are crucial. This review provides an overview of the general workflow of cryo-EM in SBDD and highlights technical innovations that enable its application in drug design. Furthermore, the most recent achievements in the cryo-EM methodology for drug discovery are discussed, demonstrating the potential of this technique for advancing drug development. By understanding the capabilities and advancements of cryo-EM, researchers can leverage the benefits of designing more effective drugs. This review concludes with a discussion of the future perspectives of cryo-EM-based SBDD, emphasizing the role of this technique in driving innovations in drug discovery and development. The integration of cryo-EM into the drug design process holds great promise for accelerating the discovery of new and improved therapeutic agents to combat various diseases.
Collapse
Affiliation(s)
| | | | | | | | - Changsuk Oh
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Kyeong Kyu Kim
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| |
Collapse
|
4
|
Liu J, Lu Y, Zhu L. A kinetic model for solving a combination optimization problem in ab-initio Cryo-EM 3D reconstruction. Brief Bioinform 2024; 25:bbad473. [PMID: 38261343 PMCID: PMC10805181 DOI: 10.1093/bib/bbad473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 10/22/2023] [Accepted: 11/28/2023] [Indexed: 01/24/2024] Open
Abstract
Cryo-Electron Microscopy (cryo-EM) is a widely used and effective method for determining the three-dimensional (3D) structure of biological molecules. For ab-initio Cryo-EM 3D reconstruction using single particle analysis (SPA), estimating the projection direction of the projection image is a crucial step. However, the existing SPA methods based on common lines are sensitive to noise. The error in common line detection will lead to a poor estimation of the projection directions and thus may greatly affect the final reconstruction results. To improve the reconstruction results, multiple candidate common lines are estimated for each pair of projection images. The key problem then becomes a combination optimization problem of selecting consistent common lines from multiple candidates. To solve the problem efficiently, a physics-inspired method based on a kinetic model is proposed in this work. More specifically, hypothetical attractive forces between each pair of candidate common lines are used to calculate a hypothetical torque exerted on each projection image in the 3D reconstruction space, and the rotation under the hypothetical torque is used to optimize the projection direction estimation of the projection image. This way, the consistent common lines along with the projection directions can be found directly without enumeration of all the combinations of the multiple candidate common lines. Compared with the traditional methods, the proposed method is shown to be able to produce more accurate 3D reconstruction results from high noise projection images. Besides the practical value, the proposed method also serves as a good reference for solving similar combinatorial optimization problems.
Collapse
Affiliation(s)
- Jiaxuan Liu
- School of Information Science and Engineering, Lanzhou
| | - Yonggang Lu
- School of Information Science and Engineering, Lanzhou
| | - Li Zhu
- School of Life Sciences, Lanzhou University
| |
Collapse
|
5
|
Chen M, Schmid MF, Chiu W. Improving resolution and resolvability of single-particle cryoEM structures using Gaussian mixture models. Nat Methods 2024; 21:37-40. [PMID: 37973972 PMCID: PMC10860619 DOI: 10.1038/s41592-023-02082-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 10/11/2023] [Indexed: 11/19/2023]
Abstract
Cryogenic electron microscopy is widely used in structural biology, but its resolution is often limited by the dynamics of the macromolecule. Here we developed a refinement protocol based on Gaussian mixture models that integrates particle orientation and conformation estimation and improves the alignment for flexible domains of protein structures. We demonstrated this protocol on multiple datasets, resulting in improved resolution and resolvability, locally and globally, by visual and quantitative measures.
Collapse
Affiliation(s)
- Muyuan Chen
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA, USA.
| | - Michael F Schmid
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA, USA
| | - Wah Chiu
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA, USA
- Department of Bioengineering, and of Microbiology and Immunology, Stanford University, Stanford, CA, USA
| |
Collapse
|
6
|
Gonzalez JP, Frandsen KEH, Kesten C. The role of intrinsic disorder in binding of plant microtubule-associated proteins to the cytoskeleton. Cytoskeleton (Hoboken) 2023; 80:404-436. [PMID: 37578201 DOI: 10.1002/cm.21773] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 07/28/2023] [Accepted: 07/30/2023] [Indexed: 08/15/2023]
Abstract
Microtubules (MTs) represent one of the main components of the eukaryotic cytoskeleton and support numerous critical cellular functions. MTs are in principle tube-like structures that can grow and shrink in a highly dynamic manner; a process largely controlled by microtubule-associated proteins (MAPs). Plant MAPs are a phylogenetically diverse group of proteins that nonetheless share many common biophysical characteristics and often contain large stretches of intrinsic protein disorder. These intrinsically disordered regions are determinants of many MAP-MT interactions, in which structural flexibility enables low-affinity protein-protein interactions that enable a fine-tuned regulation of MT cytoskeleton dynamics. Notably, intrinsic disorder is one of the major obstacles in functional and structural studies of MAPs and represents the principal present-day challenge to decipher how MAPs interact with MTs. Here, we review plant MAPs from an intrinsic protein disorder perspective, by providing a complete and up-to-date summary of all currently known members, and address the current and future challenges in functional and structural characterization of MAPs.
Collapse
Affiliation(s)
- Jordy Perez Gonzalez
- Department for Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Kristian E H Frandsen
- Department for Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Christopher Kesten
- Department for Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| |
Collapse
|
7
|
Lee SS, Park JG, Jang E, Choi SH, Kim S, Kim JW, Jin MS. W546 stacking disruption traps the human porphyrin transporter ABCB6 in an outward-facing transient state. Commun Biol 2023; 6:960. [PMID: 37735522 PMCID: PMC10514269 DOI: 10.1038/s42003-023-05339-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 09/11/2023] [Indexed: 09/23/2023] Open
Abstract
Human ATP-binding cassette transporter subfamily B6 (ABCB6) is a mitochondrial ATP-driven pump that translocates porphyrins from the cytoplasm into mitochondria for heme biosynthesis. Within the transport pathway, a conserved aromatic residue W546 located in each monomer plays a pivotal role in stabilizing the occluded conformation via π-stacking interactions. Herein, we employed cryo-electron microscopy to investigate the structural consequences of a single W546A mutation in ABCB6, both in detergent micelles and nanodiscs. The results demonstrate that the W546A mutation alters the conformational dynamics of detergent-purified ABCB6, leading to entrapment of the transporter in an outward-facing transient state. However, in the nanodisc system, we observed a direct interaction between the transporter and a phospholipid molecule that compensates for the absence of the W546 residue, thereby facilitating the normal conformational transition of the transporter toward the occluded state following ATP hydrolysis. The findings also reveal that adoption of the outward-facing conformation causes charge repulsion between ABCB6 and the bound substrate, and rearrangement of key interacting residues at the substrate-binding site. Consequently, the affinity for the substrate is significantly reduced, facilitating its release from the transporter.
Collapse
Affiliation(s)
- Sang Soo Lee
- School of Life Sciences, GIST, 123 Cheomdan-gwagiro, Buk-gu, Gwangju, 61005, Republic of Korea
| | - Jun Gyou Park
- School of Life Sciences, GIST, 123 Cheomdan-gwagiro, Buk-gu, Gwangju, 61005, Republic of Korea
| | - Eunhong Jang
- School of Life Sciences, GIST, 123 Cheomdan-gwagiro, Buk-gu, Gwangju, 61005, Republic of Korea
| | - Seung Hun Choi
- School of Life Sciences, GIST, 123 Cheomdan-gwagiro, Buk-gu, Gwangju, 61005, Republic of Korea
| | - Subin Kim
- School of Life Sciences, GIST, 123 Cheomdan-gwagiro, Buk-gu, Gwangju, 61005, Republic of Korea
| | - Ji Won Kim
- Department of Life Sciences, POSTECH, 77 Cheongam-Ro, Nam-gu, Pohang, 37673, Republic of Korea
| | - Mi Sun Jin
- School of Life Sciences, GIST, 123 Cheomdan-gwagiro, Buk-gu, Gwangju, 61005, Republic of Korea.
| |
Collapse
|
8
|
Kumar S, Singh S, Chatterjee A, Bajpai P, Sharma S, Katpara S, Lodha R, Dutta S, Luthra K. Recognition determinants of improved HIV-1 neutralization by a heavy chain matured pediatric antibody. iScience 2023; 26:107579. [PMID: 37649696 PMCID: PMC10462834 DOI: 10.1016/j.isci.2023.107579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 07/13/2023] [Accepted: 08/04/2023] [Indexed: 09/01/2023] Open
Abstract
The structural and characteristic features of HIV-1 broadly neutralizing antibodies (bnAbs) from chronically infected pediatric donors are currently unknown. Herein, we characterized a heavy chain matured HIV-1 bnAb 44m, identified from a pediatric elite-neutralizer. Interestingly, in comparison to its wild-type AIIMS-P01 bnAb, 44m exhibited moderately higher level of somatic hypermutations of 15.2%. The 44m neutralized 79% of HIV-1 heterologous viruses (n = 58) tested, with a geometric mean IC50 titer of 0.36 μg/mL. The cryo-EM structure of 44m Fab in complex with fully cleaved glycosylated native-like BG505.SOSIP.664.T332N gp140 envelope trimer at 4.4 Å resolution revealed that 44m targets the V3-glycan N332-supersite and GDIR motif to neutralize HIV-1 with improved potency and breadth, plausibly attributed by a matured heavy chain as compared to that of wild-type AIIMS-P01. This study further improves our understanding on pediatric HIV-1 bnAbs and structural basis of broad HIV-1 neutralization by 44m may be useful blueprint for vaccine design in future.
Collapse
Affiliation(s)
- Sanjeev Kumar
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi 110029, India
- ICGEB-Emory Vaccine Center, International Center for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Swarandeep Singh
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Arnab Chatterjee
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Prashant Bajpai
- ICGEB-Emory Vaccine Center, International Center for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Shaifali Sharma
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Sanket Katpara
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Rakesh Lodha
- Department of Pediatrics, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Somnath Dutta
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Kalpana Luthra
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi 110029, India
| |
Collapse
|
9
|
Majeed S, Dang L, Islam MM, Ishola O, Borbat PP, Ludtke SJ, Georgieva ER. HIV-1 Vpu protein forms stable oligomers in aqueous solution via its transmembrane domain self-association. Sci Rep 2023; 13:14691. [PMID: 37673923 PMCID: PMC10483038 DOI: 10.1038/s41598-023-41873-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 09/01/2023] [Indexed: 09/08/2023] Open
Abstract
We report our findings on the assembly of the HIV-1 protein Vpu into soluble oligomers. Vpu is a key HIV-1 protein. It has been considered exclusively a single-pass membrane protein. Previous observations show that this protein forms stable oligomers in aqueous solution, but details about these oligomers still remain obscure. This is an interesting and rather unique observation, as the number of proteins transitioning between soluble and membrane embedded states is limited. In this study we made use of protein engineering, size exclusion chromatography, cryoEM and electron paramagnetic resonance (EPR) spectroscopy to better elucidate the nature of the soluble oligomers. We found that Vpu oligomerizes via its N-terminal transmembrane domain (TM). CryoEM suggests that the oligomeric state most likely is a hexamer/heptamer equilibrium. Both cryoEM and EPR suggest that, within the oligomer, the distal C-terminal region of Vpu is highly flexible. Our observations are consistent with both the concept of specific interactions among TM helices or the core of the oligomers being stabilized by hydrophobic forces. While this study does not resolve all of the questions about Vpu oligomers or their functional role in HIV-1 it provides new fundamental information about the size and nature of the oligomeric interactions.
Collapse
Affiliation(s)
- Saman Majeed
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409, USA
| | - Lan Dang
- Graduate Program in Quantitative and Computational Biosciences, Graduate School of Biomedical Sciences at Baylor College of Medicine, Houston, TX, USA
| | - Md Majharul Islam
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409, USA
| | - Olamide Ishola
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409, USA
| | - Peter P Borbat
- Department of Chemistry and Chemical Biology and ACERT, Cornell University, Ithaca, NY, 14853, USA
| | - Steven J Ludtke
- Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Elka R Georgieva
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409, USA.
- Center for Membrane Protein Research, TTU Health Science Center, Lubbock, TX, 79430, USA.
| |
Collapse
|
10
|
Kim C, Schlicksup CJ, Pérez-Segura C, Hadden-Perilla JA, Wang JCY, Zlotnick A. Structure of the Hepatitis B virus capsid quasi-6-fold with a trapped C-terminal domain reveals capsid movements associated with domain exit. J Biol Chem 2023; 299:105104. [PMID: 37517693 PMCID: PMC10463254 DOI: 10.1016/j.jbc.2023.105104] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 07/08/2023] [Accepted: 07/11/2023] [Indexed: 08/01/2023] Open
Abstract
Many viruses undergo transient conformational change to surveil their environments for receptors and host factors. In Hepatitis B virus (HBV) infection, after the virus enters the cell, it is transported to the nucleus by interaction of the HBV capsid with an importin α/β complex. The interaction between virus and importins is mediated by nuclear localization signals on the capsid protein's C-terminal domain (CTD). However, CTDs are located inside the capsid. In this study, we asked where does a CTD exit the capsid, are all quasi-equivalent CTDs created equal, and does the capsid structure deform to facilitate CTD egress from the capsid? Here, we used Impβ as a tool to trap transiently exposed CTDs and examined this complex by cryo-electron microscopy. We examined an asymmetric reconstruction of a T = 4 icosahedral capsid and a focused reconstruction of a quasi-6-fold vertex (3.8 and 4.0 Å resolution, respectively). Both approaches showed that a subset of CTDs extended through a pore in the center of the quasi-6-fold complex. CTD egress was accompanied by enlargement of the pore and subtle changes in quaternary and tertiary structure of the quasi-6-fold. When compared to molecular dynamics simulations, structural changes were within the normal range of capsid flexibility. Although pore diameter was enlarged in the Impβ-bound reconstruction, simulations indicate that CTD egress does not exclusively depend on enlarged pores. In summary, we find that HBV surveillance of its environment by transient exposure of its CTD requires only modest conformational change of the capsid.
Collapse
Affiliation(s)
- Christine Kim
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
| | | | - Carolina Pérez-Segura
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, USA
| | - Jodi A Hadden-Perilla
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, USA
| | - Joseph Che-Yen Wang
- Department of Microbiology & Immunology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
| | - Adam Zlotnick
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA.
| |
Collapse
|
11
|
Grassetti AV, May MB, Davis JH. Application of monolayer graphene to cryo-electron microscopy grids for high-resolution structure determination. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.28.550908. [PMID: 37546934 PMCID: PMC10402136 DOI: 10.1101/2023.07.28.550908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
In cryogenic electron microscopy (cryo-EM), purified macromolecules are typically applied to a grid bearing a holey carbon foil, blotted to remove excess liquid and rapidly frozen in a roughly 20-100 nm thick layer of vitreous ice that is suspended across roughly 1 μm-wide foil holes. The resulting sample is then imaged using cryogenic transmission electron microscopy and, after substantial image processing, near-atomic resolution structures can be determined. Despite cryo-EM's widespread adoption, sample preparation remains a severe bottleneck in cryo-EM workflows, with users often encountering challenges related to samples behaving poorly in the suspended vitreous ice. Recently, methods have been developed to modify cryo-EM grids with a single continuous layer of graphene, which acts as a support surface that often increases particle density in the imaged area and can reduce interactions between particles and the air-water interface. Here, we provide detailed protocols for the application of graphene to cryo-EM grids, and for rapidly assessing the relative hydrophilicity of the resulting grids. Additionally, we describe an EM-based method to confirm the presence of graphene by visualizing its characteristic diffraction pattern. Finally, we demonstrate the utility of these graphene supports by rapidly reconstructing a 2.7 Å resolution density map of an exemplar Cas9 complex using a highly pure sample at a relatively low concentration.
Collapse
Affiliation(s)
- Andrew V. Grassetti
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Mira B. May
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Joseph H. Davis
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
- Program in Computational and Systems Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| |
Collapse
|
12
|
Huet A, Oh B, Maurer J, Duda RL, Conway JF. A symmetry mismatch unraveled: How phage HK97 scaffold flexibly accommodates a 12-fold pore at a 5-fold viral capsid vertex. SCIENCE ADVANCES 2023; 9:eadg8868. [PMID: 37327331 PMCID: PMC10275583 DOI: 10.1126/sciadv.adg8868] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 05/12/2023] [Indexed: 06/18/2023]
Abstract
Tailed bacteriophages and herpesviruses use a transient scaffold to assemble icosahedral capsids with hexameric capsomers on the faces and pentameric capsomers at all but one vertex where a 12-fold portal is thought to nucleate the assembly. How does the scaffold orchestrate this step? We have determined the portal vertex structure of the bacteriophage HK97 procapsid, where the scaffold is a domain of the major capsid protein. The scaffold forms rigid helix-turn-strand structures on the interior surfaces of all capsomers and is further stabilized around the portal, forming trimeric coiled-coil towers, two per surrounding capsomer. These 10 towers bind identically to 10 of 12 portal subunits, adopting a pseudo-12-fold organization that explains how the symmetry mismatch is managed at this early step.
Collapse
Affiliation(s)
- Alexis Huet
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Bonnie Oh
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Josh Maurer
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Robert L. Duda
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - James F. Conway
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| |
Collapse
|
13
|
Baldwin PR. Transformations between rotational and translational invariants formulated in reciprocal spaces. J Struct Biol X 2023; 7:100089. [PMID: 37398937 PMCID: PMC10314203 DOI: 10.1016/j.yjsbx.2023.100089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2023] Open
Abstract
Correlation functions play an important role in the theoretical underpinnings of many disparate areas of the physical sciences: in particular, scattering theory. More recently, they have become useful in the classification of objects in areas such as computer vision and our area of cryoEM. Our primary classification scheme in the cryoEM image processing system, EMAN2, is now based on third order invariants formulated in Fourier space. This allows a factor of 8 speed up in the two classification procedures inherent in our software pipeline, because it allows for classification without the need for computationally costly alignment procedures. In this work, we address several formal and practical aspects of such multispectral invariants. We show that we can formulate such invariants in the representation in which the original signal is most compact. We explicitly construct transformations between invariants in different orientations for arbitrary order of correlation functions and dimension. We demonstrate that third order invariants distinguish 2D mirrored patterns (unlike the radial power spectrum), which is a fundamental aspects of its classification efficacy. We show the limitations of 3rd order invariants also, by giving an example of a wide family of patterns with identical (vanishing) set of 3rd order invariants. For sufficiently rich patterns, the third order invariants should distinguish typical images, textures and patterns.
Collapse
|
14
|
Chen M, Toader B, Lederman R. Integrating Molecular Models Into CryoEM Heterogeneity Analysis Using Scalable High-resolution Deep Gaussian Mixture Models. J Mol Biol 2023; 435:168014. [PMID: 36806476 PMCID: PMC10164680 DOI: 10.1016/j.jmb.2023.168014] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 02/07/2023] [Accepted: 02/08/2023] [Indexed: 02/17/2023]
Abstract
Resolving the structural variability of proteins is often key to understanding the structure-function relationship of those macromolecular machines. Single particle analysis using Cryogenic electron microscopy (CryoEM), combined with machine learning algorithms, provides a way to reveal the dynamics within the protein system from noisy micrographs. Here, we introduce an improved computational method that uses Gaussian mixture models for protein structure representation and deep neural networks for conformation space embedding. By integrating information from molecular models into the heterogeneity analysis, we can analyze continuous protein conformational changes using structural information at the frequency of 1/3 Å-1, and present the results in a more interpretable form.
Collapse
Affiliation(s)
- Muyuan Chen
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA, USA
| | - Bogdan Toader
- Department of Statistics and Data Science, Yale University, New Haven, CT, USA
| | - Roy Lederman
- Department of Statistics and Data Science, Yale University, New Haven, CT, USA
| |
Collapse
|
15
|
Zeng X, Kahng A, Xue L, Mahamid J, Chang YW, Xu M. High-throughput cryo-ET structural pattern mining by unsupervised deep iterative subtomogram clustering. Proc Natl Acad Sci U S A 2023; 120:e2213149120. [PMID: 37027429 PMCID: PMC10104553 DOI: 10.1073/pnas.2213149120] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 02/24/2023] [Indexed: 04/08/2023] Open
Abstract
Cryoelectron tomography directly visualizes heterogeneous macromolecular structures in their native and complex cellular environments. However, existing computer-assisted structure sorting approaches are low throughput or inherently limited due to their dependency on available templates and manual labels. Here, we introduce a high-throughput template-and-label-free deep learning approach, Deep Iterative Subtomogram Clustering Approach (DISCA), that automatically detects subsets of homogeneous structures by learning and modeling 3D structural features and their distributions. Evaluation on five experimental cryo-ET datasets shows that an unsupervised deep learning based method can detect diverse structures with a wide range of molecular sizes. This unsupervised detection paves the way for systematic unbiased recognition of macromolecular complexes in situ.
Collapse
Affiliation(s)
- Xiangrui Zeng
- Computational Biology Department, Carnegie Mellon University, Pittsburgh, PA15213
| | - Anson Kahng
- Computer Science Department, University of Rochester, Rochester, NY14620
| | - Liang Xue
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg69117, Germany
- Faculty of Biosciences, Collaboration for joint PhD degree between European Molecular Biology Laboratory and Heidelberg University, Heidelberg69117, Germany
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg69117, Germany
| | - Yi-Wei Chang
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA19104
| | - Min Xu
- Computational Biology Department, Carnegie Mellon University, Pittsburgh, PA15213
| |
Collapse
|
16
|
Marchenkov V, Ivashina T, Marchenko N, Ryabova N, Selivanova O, Timchenko A, Kihara H, Ksenzenko V, Semisotnov G. In Vivo Incorporation of Photoproteins into GroEL Chaperonin Retaining Major Structural and Functional Properties. Molecules 2023; 28:molecules28041901. [PMID: 36838891 PMCID: PMC9965216 DOI: 10.3390/molecules28041901] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 02/12/2023] [Accepted: 02/14/2023] [Indexed: 02/19/2023] Open
Abstract
The incorporation of photoproteins into proteins of interest allows the study of either their localization or intermolecular interactions in the cell. Here we demonstrate the possibility of in vivo incorporating the photoprotein Aequorea victoria enhanced green fluorescent protein (EGFP) or Gaussia princeps luciferase (GLuc) into the tetradecameric quaternary structure of GroEL chaperonin and describe some physicochemical properties of the labeled chaperonin. Using size-exclusion and affinity chromatography, electrophoresis, fluorescent and electron transmission microscopy (ETM), small-angle X-ray scattering (SAXS), and bioluminescence resonance energy transfer (BRET), we show the following: (i) The GroEL14-EGFP is evenly distributed within normally divided E. coli cells, while gigantic undivided cells are characterized by the uneven distribution of the labeled GroEL14 which is mainly localized close to the cellular periplasm; (ii) EGFP and likely GLuc are located within the inner cavity of one of the two GroEL chaperonin rings and do not essentially influence the protein oligomeric structure; (iii) GroEL14 containing either EGFP or GLuc is capable of interacting with non-native proteins and the cochaperonin GroES.
Collapse
Affiliation(s)
- Victor Marchenkov
- Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya St., 142290 Pushchino, Russia
| | - Tanya Ivashina
- Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospect Nauki, 142290 Pushchino, Russia
| | - Natalia Marchenko
- Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya St., 142290 Pushchino, Russia
| | - Natalya Ryabova
- Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya St., 142290 Pushchino, Russia
| | - Olga Selivanova
- Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya St., 142290 Pushchino, Russia
| | - Alexander Timchenko
- Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya St., 142290 Pushchino, Russia
| | - Hiroshi Kihara
- Department of Physics, Kansai Medical University, Shin-Machi 2-5-1, Hirakata 573-1010, Japan
| | - Vladimir Ksenzenko
- Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya St., 142290 Pushchino, Russia
| | - Gennady Semisotnov
- Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya St., 142290 Pushchino, Russia
- Correspondence: ; Tel.: +7-(496)-731-8409
| |
Collapse
|
17
|
George A, Kim DN, Moser T, Gildea IT, Evans JE, Cheung MS. Graph identification of proteins in tomograms (GRIP-Tomo). Protein Sci 2023; 32:e4538. [PMID: 36482866 PMCID: PMC9798246 DOI: 10.1002/pro.4538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/23/2022] [Accepted: 12/03/2022] [Indexed: 12/14/2022]
Abstract
In this study, we present a method of pattern mining based on network theory that enables the identification of protein structures or complexes from synthetic volume densities, without the knowledge of predefined templates or human biases for refinement. We hypothesized that the topological connectivity of protein structures is invariant, and they are distinctive for the purpose of protein identification from distorted data presented in volume densities. Three-dimensional densities of a protein or a complex from simulated tomographic volumes were transformed into mathematical graphs as observables. We systematically introduced data distortion or defects such as missing fullness of data, the tumbling effect, and the missing wedge effect into the simulated volumes, and varied the distance cutoffs in pixels to capture the varying connectivity between the density cluster centroids in the presence of defects. A similarity score between the graphs from the simulated volumes and the graphs transformed from the physical protein structures in point data was calculated by comparing their network theory order parameters including node degrees, betweenness centrality, and graph densities. By capturing the essential topological features defining the heterogeneous morphologies of a network, we were able to accurately identify proteins and homo-multimeric complexes from 10 topologically distinctive samples without realistic noise added. Our approach empowers future developments of tomogram processing by providing pattern mining with interpretability, to enable the classification of single-domain protein native topologies as well as distinct single-domain proteins from multimeric complexes within noisy volumes.
Collapse
Affiliation(s)
- August George
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, USA.,Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, USA
| | - Doo Nam Kim
- Biological Science Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Trevor Moser
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Ian T Gildea
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - James E Evans
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, USA.,School of Biological Sciences, Washington State University, Pullman, Washington, USA
| | - Margaret S Cheung
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, USA.,Department of Physics, University of Washington, Seattle, Washington, USA
| |
Collapse
|
18
|
Weerachatyanukul W, Kiatmetha P, Raksat P, Boonkua S, Thongsum O, Jariyapong P, Chotwiwatthanakun C, Ounjai P, Metlagel Z. Viral Capsid Change upon Encapsulation of Double-Stranded DNA into an Infectious Hypodermal and Hematopoietic Necrosis Virus-like Particle. Viruses 2022; 15:110. [PMID: 36680151 PMCID: PMC9867196 DOI: 10.3390/v15010110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 12/20/2022] [Accepted: 12/26/2022] [Indexed: 01/04/2023] Open
Abstract
In this study, we aimed to encapsulate the sizable double-stranded DNA (dsDNA, 3.9 kbp) into a small-sized infectious hypodermal and hematopoietic necrosis virus-like particle (IHHNV-VLP; T = 1) and compared the changes in capsid structure between dsDNA-filled VLP and empty VLP. Based on our encapsulation protocol, IHHNV-VLP was able to load dsDNA at an efficiency of 30-40% (w/w) into its cavity. Structural analysis revealed two subclasses of IHHNV-VLP, so-called empty and dsDNA-filled VLPs. The three-dimensional (3D) structure of the empty VLP produced in E. coli was similar to that of the empty IHHNV-VLP produced in Sf9 insect cells. The size of the dsDNA-filled VLP was slightly bigger (50 Å) than its empty VLP counterpart; however, the capsid structure was drastically altered. The capsid was about 1.5-fold thicker due to the thickening of the capsid interior, presumably from DNA-capsid interaction evident from capsid protrusions or nodules on the interior surface. In addition, the morphological changes of the capsid exterior were particularly observed in the vicinity of the five-fold axes, where the counter-clockwise twisting of the "tripod" structure at the vertex of the five-fold channel was evident, resulting in a widening of the channel's opening. Whether these capsid changes are similar to virion capsid maturation in the host cells remains to be investigated. Nevertheless, the ability of IHHNV-VLP to encapsulate the sizable dsDNA has opened up the opportunity to package a dsDNA vector that can insert exogenous genes and target susceptible shrimp cells in order to halt viral infection.
Collapse
Affiliation(s)
- Wattana Weerachatyanukul
- Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Rd., Ratchathewi, Bangkok 10400, Thailand
| | - Pauline Kiatmetha
- Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Rd., Ratchathewi, Bangkok 10400, Thailand
| | - Ponlawoot Raksat
- Department of Biology, Faculty of Science, Mahidol University, Ratchathewi, Bangkok 10400, Thailand
| | - Supawich Boonkua
- Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Rd., Ratchathewi, Bangkok 10400, Thailand
| | - Orawan Thongsum
- Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Rd., Ratchathewi, Bangkok 10400, Thailand
| | - Pitchanee Jariyapong
- Department of Medical Science, School of Medicine, Walailak University, Thasala District, Nakhonsrithammarat 80160, Thailand
| | | | - Puey Ounjai
- Department of Biology, Faculty of Science, Mahidol University, Ratchathewi, Bangkok 10400, Thailand
| | - Zoltan Metlagel
- Lawrence Berkeley National Laboratory, Molecular Biophysics and Integrated Bioimaging Division, University of California, Berkeley, CA 94720, USA
| |
Collapse
|
19
|
Alphavirus Particles Can Assemble with an Alternate Triangulation Number. Viruses 2022; 14:v14122650. [PMID: 36560655 PMCID: PMC9780915 DOI: 10.3390/v14122650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/24/2022] [Accepted: 11/25/2022] [Indexed: 11/29/2022] Open
Abstract
Alphaviruses are spherical, enveloped RNA viruses primarily transmitted by mosquitoes, and cause significant arthritogenic and neurotropic disease in humans and livestock. Previous reports have shown that-in contrast to prototypical icosahedral viruses-alphaviruses incorporate frequent defects, and these may serve important functions in the viral life cycle. We confirm the genus-wide pleomorphism in live viral particles and extend our understanding of alphavirus assembly through the discovery of an alternate architecture of Eastern equine encephalitis virus (EEEV) particles. The alternate T = 3 icosahedral architecture differs in triangulation number from the classic T = 4 icosahedral organization that typifies alphaviruses, but the alternate architecture maintains the quasi-equivalence relationship of asymmetric units. The fusion spike glycoproteins are more loosely apposed in the T = 3 form with corresponding changes in the underlying capsid protein lattice. This alternate architecture could potentially be exploited in engineering alphavirus-based particles for delivery of alphaviral or other RNA.
Collapse
|
20
|
Yu X, Yi P, Panigrahi AK, Lumahan LEV, Lydon JP, Lonard DM, Lutdke SJ, Wang Z, O'Malley BW. Spatial definition of the human progesterone receptor-B transcriptional complex. iScience 2022; 25:105321. [PMID: 36325049 PMCID: PMC9618773 DOI: 10.1016/j.isci.2022.105321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/27/2022] [Accepted: 10/07/2022] [Indexed: 01/09/2023] Open
Abstract
We report the quaternary structure of core transcriptional complex for the full-length human progesterone receptor-B (PR-B) homodimer with primary coactivator steroid receptor coactivator-2 (SRC-2) and the secondary coactivator p300/CREB-binding protein (CBP). The PR-B homodimer engages one SRC-2 mainly through its activation function 1 (AF1) in N-terminus. SRC-2 is positioned between PR-B and p300 leaving space for direct interaction between PR-B and p300 through PR-B's C-terminal AF2 and its unique AF3. Direct AF3/p300 interaction provides long-desired structural insights into the known functional differences between PR-B and the PR-A isoform lacking AF3. We reveal the contributions of each AF and demonstrate their structural basis in forming the PR-B dimer interface and PR-B/coactivator complex. Comparison of the PR-B/coactivator complex with other steroid receptor (estrogen receptor and androgen receptor) complexes also shows that each receptor has its unique mechanism for recruiting coactivators due to the highly variable N-termini among receptors.
Collapse
Affiliation(s)
- Xinzhe Yu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.,Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ping Yi
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.,Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA.,Center for Nuclear Receptor and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Anil K Panigrahi
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lance Edward V Lumahan
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - John P Lydon
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - David M Lonard
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Steven J Lutdke
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.,CryoEM/ET Core, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhao Wang
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.,Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.,CryoEM/ET Core, Baylor College of Medicine, Houston, TX 77030, USA.,Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Bert W O'Malley
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.,Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA
| |
Collapse
|
21
|
Raghavan SSR, Dagil R, Lopez-Perez M, Conrad J, Bassi MR, Quintana MDP, Choudhary S, Gustavsson T, Wang Y, Gourdon P, Ofori MF, Christensen SB, Minja DTR, Schmiegelow C, Nielsen MA, Barfod L, Hviid L, Salanti A, Lavstsen T, Wang K. Cryo-EM reveals the conformational epitope of human monoclonal antibody PAM1.4 broadly reacting with polymorphic malarial protein VAR2CSA. PLoS Pathog 2022; 18:e1010924. [PMCID: PMC9668162 DOI: 10.1371/journal.ppat.1010924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 10/10/2022] [Indexed: 11/17/2022] Open
Abstract
Malaria during pregnancy is a major global health problem caused by infection with Plasmodium falciparum parasites. Severe effects arise from the accumulation of infected erythrocytes in the placenta. Here, erythrocytes infected by late blood-stage parasites adhere to placental chondroitin sulphate A (CS) via VAR2CSA-type P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesion proteins. Immunity to placental malaria is acquired through exposure and mediated through antibodies to VAR2CSA. Through evolution, the VAR2CSA proteins have diversified in sequence to escape immune recognition but retained their overall macromolecular structure to maintain CS binding affinity. This structural conservation may also have allowed development of broadly reactive antibodies to VAR2CSA in immune women. Here we show the negative stain and cryo-EM structure of the only known broadly reactive human monoclonal antibody, PAM1.4, in complex with VAR2CSA. The data shows how PAM1.4’s broad VAR2CSA reactivity is achieved through interactions with multiple conserved residues of different sub-domains forming conformational epitope distant from the CS binding site on the VAR2CSA core structure. Thus, while PAM1.4 may represent a class of antibodies mediating placental malaria immunity by inducing phagocytosis or NK cell-mediated cytotoxicity, it is likely that broadly CS binding-inhibitory antibodies target other epitopes at the CS binding site. Insights on both types of broadly reactive monoclonal antibodies may aid the development of a vaccine against placental malaria.
Collapse
Affiliation(s)
- Sai Sundar Rajan Raghavan
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Robert Dagil
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Mary Lopez-Perez
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Julian Conrad
- Swedish National Cryo-EM Facility, Science for Life Laboratories, Solna, Sweden
| | - Maria Rosaria Bassi
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Maria del Pilar Quintana
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Swati Choudhary
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Tobias Gustavsson
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Yong Wang
- Joint Research Centre for Engineering Biology, Zhejiang University-University of Edinburgh Institute, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Pontus Gourdon
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Michael Fokuo Ofori
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Sebastian Boje Christensen
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | | | - Christentze Schmiegelow
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Morten Agertoug Nielsen
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Lea Barfod
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Lars Hviid
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Ali Salanti
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Thomas Lavstsen
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
- * E-mail: (TL); (KW)
| | - Kaituo Wang
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- * E-mail: (TL); (KW)
| |
Collapse
|
22
|
The lysosomal transporter TAPL has a dual role as peptide translocator and phosphatidylserine floppase. Nat Commun 2022; 13:5851. [PMID: 36195619 PMCID: PMC9532399 DOI: 10.1038/s41467-022-33593-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 09/23/2022] [Indexed: 11/08/2022] Open
Abstract
TAPL is a lysosomal ATP-binding cassette transporter that translocates a broad spectrum of polypeptides from the cytoplasm into the lysosomal lumen. Here we report that, in addition to its well-known role as a peptide translocator, TAPL exhibits an ATP-dependent phosphatidylserine floppase activity that is the possible cause of its high basal ATPase activity and of the lack of coupling between ATP hydrolysis and peptide efflux. We also present the cryo-EM structures of mouse TAPL complexed with (i) phospholipid, (ii) cholesteryl hemisuccinate (CHS) and 9-mer peptide, and (iii) ADP·BeF3. The inward-facing structure reveals that F449 protrudes into the cylindrical transport pathway and divides it into a large hydrophilic central cavity and a sizable hydrophobic upper cavity. In the structure, the peptide binds to TAPL in horizontally-stretched fashion within the central cavity, while lipid molecules plug vertically into the upper cavity. Together, our results suggest that TAPL uses different mechanisms to function as a peptide translocase and a phosphatidylserine floppase.
Collapse
|
23
|
Wang Z, Muecksch F, Muenn F, Cho A, Zong S, Raspe R, Ramos V, Johnson B, Ben Tanfous T, DaSilva J, Bednarski E, Guzman-Cardozo C, Turroja M, Millard KG, Tober-Lau P, Hillus D, Yao KH, Shimeliovich I, Dizon J, Kaczynska A, Jankovic M, Gazumyan A, Oliveira TY, Caskey M, Bieniasz PD, Hatziioannou T, Kurth F, Sander LE, Nussenzweig MC, Gaebler C. Humoral immunity to SARS-CoV-2 elicited by combination COVID-19 vaccination regimens. J Exp Med 2022; 219:e20220826. [PMID: 36006380 PMCID: PMC9418484 DOI: 10.1084/jem.20220826] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/19/2022] [Accepted: 07/13/2022] [Indexed: 11/04/2022] Open
Abstract
The SARS-CoV-2 pandemic prompted a global vaccination effort and the development of numerous COVID-19 vaccines at an unprecedented scale and pace. As a result, current COVID-19 vaccination regimens comprise diverse vaccine modalities, immunogen combinations, and dosing intervals. Here, we compare vaccine-specific antibody and memory B cell responses following two-dose mRNA, single-dose Ad26.COV.2S, and two-dose ChAdOx1, or combination ChAdOx1/mRNA vaccination. Plasma-neutralizing activity, as well as the magnitude, clonal composition, and antibody maturation of the RBD-specific memory B cell compartments, showed substantial differences between the vaccination regimens. While individual monoclonal antibodies derived from memory B cells exhibited similar binding affinities and neutralizing potency against Wuhan-Hu-1 SARS-CoV-2, there were significant differences in epitope specificity and neutralizing breadth against viral variants of concern. Although the ChAdOx1 vaccine was inferior to mRNA and Ad26.COV.2S in several respects, biochemical and structural analyses revealed enrichment in a subgroup of memory B cell neutralizing antibodies with distinct RBD-binding properties resulting in remarkable potency and breadth.
Collapse
Affiliation(s)
- Zijun Wang
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
| | - Frauke Muecksch
- Laboratory of Retrovirology, The Rockefeller University, New York, NY
| | - Friederike Muenn
- Department of Infectious Diseases and Respiratory Medicine, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Alice Cho
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
| | - Shuai Zong
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
| | - Raphael Raspe
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
| | - Victor Ramos
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
| | - Brianna Johnson
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
| | - Tarek Ben Tanfous
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
| | - Justin DaSilva
- Laboratory of Retrovirology, The Rockefeller University, New York, NY
| | - Eva Bednarski
- Laboratory of Retrovirology, The Rockefeller University, New York, NY
| | | | - Martina Turroja
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
| | - Katrina G. Millard
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
| | - Pinkus Tober-Lau
- Department of Infectious Diseases and Respiratory Medicine, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - David Hillus
- Department of Infectious Diseases and Respiratory Medicine, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Kai-Hui Yao
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
| | - Irina Shimeliovich
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
| | - Juan Dizon
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
| | - Anna Kaczynska
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
| | - Mila Jankovic
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
| | - Anna Gazumyan
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
| | - Thiago Y. Oliveira
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
| | - Marina Caskey
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
| | - Paul D. Bieniasz
- Laboratory of Retrovirology, The Rockefeller University, New York, NY
- Howard Hughes Medical Institute, The Rockefeller University, New York, NY
| | | | - Florian Kurth
- Department of Infectious Diseases and Respiratory Medicine, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Leif Erik Sander
- Department of Infectious Diseases and Respiratory Medicine, Charité–Universitätsmedizin Berlin, Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
| | - Michel C. Nussenzweig
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
- Howard Hughes Medical Institute, The Rockefeller University, New York, NY
| | - Christian Gaebler
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY
- Department of Infectious Diseases and Respiratory Medicine, Charité–Universitätsmedizin Berlin, Berlin, Germany
| |
Collapse
|
24
|
SARS-CoV-2 variants of concern: spike protein mutational analysis and epitope for broad neutralization. Nat Commun 2022; 13:4696. [PMID: 35982054 PMCID: PMC9388680 DOI: 10.1038/s41467-022-32262-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 07/21/2022] [Indexed: 11/18/2022] Open
Abstract
Mutations in the spike glycoproteins of SARS-CoV-2 variants of concern have independently been shown to enhance aspects of spike protein fitness. Here, we describe an antibody fragment (VH ab6) that neutralizes all major variants including the recently emerged BA.1 and BA.2 Omicron subvariants, with a unique mode of binding revealed by cryo-EM studies. Further, we provide a comparative analysis of the mutational effects within previously emerged variant spikes and identify the structural role of mutations within the NTD and RBD in evading antibody neutralization. Our analysis shows that the highly mutated Gamma N-terminal domain exhibits considerable structural rearrangements, partially explaining its decreased neutralization by convalescent sera. Our results provide mechanistic insights into the structural, functional, and antigenic consequences of SARS-CoV-2 spike mutations and highlight a spike protein vulnerability that may be exploited to achieve broad protection against circulating variants. SARS-CoV-2 variants have accumulated multiple defining mutations within their spike glycoproteins. Here, the authors report a structural basis for broad neutralization of several variants by a heavy chain antibody fragment and provide a mutational analysis focusing on antibody evasion, receptor engagement, and spike protein structure.
Collapse
|
25
|
Jenni S, Horwitz JA, Bloyet LM, Whelan SPJ, Harrison SC. Visualizing molecular interactions that determine assembly of a bullet-shaped vesicular stomatitis virus particle. Nat Commun 2022; 13:4802. [PMID: 35970826 PMCID: PMC9378655 DOI: 10.1038/s41467-022-32223-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 07/18/2022] [Indexed: 11/09/2022] Open
Abstract
Vesicular stomatitis virus (VSV) is a negative-strand RNA virus with a non-segmented genome, closely related to rabies virus. Both have characteristic bullet-like shapes. We report the structure of intact, infectious VSV particles determined by cryogenic electron microscopy. By compensating for polymorphism among viral particles with computational classification, we obtained a reconstruction of the shaft ("trunk") at 3.5 Å resolution, with lower resolution for the rounded tip. The ribonucleoprotein (RNP), genomic RNA complexed with nucleoprotein (N), curls into a dome-like structure with about eight gradually expanding turns before transitioning into the regular helical trunk. Two layers of matrix (M) protein link the RNP with the membrane. Radial inter-layer subunit contacts are fixed within single RNA-N-M1-M2 modules, but flexible lateral and axial interactions allow assembly of polymorphic virions. Together with published structures of recombinant N in various states, our results suggest a mechanism for membrane-coupled self-assembly of VSV and its relatives.
Collapse
Affiliation(s)
- Simon Jenni
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA.
| | - Joshua A Horwitz
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA.,Department of Microbiology, Harvard Medical School, Boston, MA, 02115, USA.,Molecular Pharmacology and Virology Group, PureTech Health LLC, Boston, MA, 02210, USA
| | - Louis-Marie Bloyet
- Department of Microbiology, Harvard Medical School, Boston, MA, 02115, USA.,Department of Molecular Microbiology, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Sean P J Whelan
- Department of Microbiology, Harvard Medical School, Boston, MA, 02115, USA.,Department of Molecular Microbiology, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Stephen C Harrison
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA. .,Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, 02115, USA. .,Laboratory of Molecular Medicine, Boston Children's Hospital, Boston, MA, 02115, USA.
| |
Collapse
|
26
|
Computational methods for ultrastructural analysis of synaptic complexes. Curr Opin Neurobiol 2022; 76:102611. [PMID: 35952541 DOI: 10.1016/j.conb.2022.102611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 11/21/2022]
Abstract
Electron microscopy (EM) provided fundamental insights about the ultrastructure of neuronal synapses. The large amount of information present in the contemporary EM datasets precludes a thorough assessment by visual inspection alone, thus requiring computational methods for the analysis of the data. Here, I review image processing software methods ranging from membrane tracing in large volume datasets to high resolution structures of synaptic complexes. Particular attention is payed to molecular level analysis provided by recent cryo-electron microscopy and tomography methods.
Collapse
|
27
|
Potent and broad neutralization of SARS-CoV-2 variants of concern (VOCs) including omicron sub-lineages BA.1 and BA.2 by biparatopic human VH domains. iScience 2022; 25:104798. [PMID: 35875685 PMCID: PMC9296231 DOI: 10.1016/j.isci.2022.104798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 06/08/2022] [Accepted: 07/14/2022] [Indexed: 12/24/2022] Open
Abstract
The emergence of SARS-CoV-2 variants of concern (VOCs) requires the development of next-generation biologics with high neutralization breadth. Here, we characterized a human VH domain, F6, which we generated by sequentially panning large phage-displayed VH libraries against receptor binding domains (RBDs) containing VOC mutations. Cryo-EM analyses reveal that F6 has a unique binding mode that spans a broad surface of the RBD and involves the antibody framework region. Attachment of an Fc region to a fusion of F6 and ab8, a previously characterized VH domain, resulted in a construct (F6-ab8-Fc) that broadly and potently neutralized VOCs including Omicron. Additionally, prophylactic treatment using F6-ab8-Fc reduced live Beta (B.1.351) variant viral titers in the lungs of a mouse model. Our results provide a new potential therapeutic against SARS-CoV-2 variants including Omicron and highlight a vulnerable epitope within the spike that may be exploited to achieve broad protection against circulating variants.
Collapse
|
28
|
Sheng Y, Morris K, Radecke J, Zhang P. Cryo-electron Tomography Remote Data Collection and Subtomogram Averaging. J Vis Exp 2022:10.3791/63923. [PMID: 35913165 PMCID: PMC10006545 DOI: 10.3791/63923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Cryo-electron tomography (cryo-ET) has been gaining momentum in recent years, especially since the introduction of direct electron detectors, improved automated acquisition strategies, preparative techniques that expand the possibilities of what the electron microscope can image at high-resolution using cryo-ET and new subtomogram averaging software. Additionally, data acquisition has become increasingly streamlined, making it more accessible to many users. The SARS-CoV-2 pandemic has further accelerated remote cryo-electron microscopy (cryo-EM) data collection, especially for single-particle cryo-EM, in many facilities globally, providing uninterrupted user access to state-of-the-art instruments during the pandemic. With the recent advances in Tomo5 (software for 3D electron tomography), remote cryo-ET data collection has become robust and easy to handle from anywhere in the world. This article aims to provide a detailed walk-through, starting from the data collection setup in the tomography software for the process of a (remote) cryo-ET data collection session with detailed troubleshooting. The (remote) data collection protocol is further complemented with the workflow for structure determination at near-atomic resolution by subtomogram averaging with emClarity, using apoferritin as an example.
Collapse
Affiliation(s)
- Yuewen Sheng
- Electron Bio-Imaging Centre, Diamond Light Source Ltd, Harwell Science & Innovation Campus
| | - Kyle Morris
- Electron Bio-Imaging Centre, Diamond Light Source Ltd, Harwell Science & Innovation Campus
| | - Julika Radecke
- Electron Bio-Imaging Centre, Diamond Light Source Ltd, Harwell Science & Innovation Campus;
| | - Peijun Zhang
- Electron Bio-Imaging Centre, Diamond Light Source Ltd, Harwell Science & Innovation Campus; Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford; Chinese Academy of Medical Sciences Oxford Institute, University of Oxford;
| |
Collapse
|
29
|
Wang Z, Muecksch F, Cho A, Gaebler C, Hoffmann HH, Ramos V, Zong S, Cipolla M, Johnson B, Schmidt F, DaSilva J, Bednarski E, Ben Tanfous T, Raspe R, Yao K, Lee YE, Chen T, Turroja M, Milard KG, Dizon J, Kaczynska A, Gazumyan A, Oliveira TY, Rice CM, Caskey M, Bieniasz PD, Hatziioannou T, Barnes CO, Nussenzweig MC. Analysis of memory B cells identifies conserved neutralizing epitopes on the N-terminal domain of variant SARS-Cov-2 spike proteins. Immunity 2022; 55:998-1012.e8. [PMID: 35447092 PMCID: PMC8986478 DOI: 10.1016/j.immuni.2022.04.003] [Citation(s) in RCA: 57] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/15/2022] [Accepted: 04/01/2022] [Indexed: 11/17/2022]
Abstract
SARS-CoV-2 infection or vaccination produces neutralizing antibody responses that contribute to better clinical outcomes. The receptor-binding domain (RBD) and the N-terminal domain (NTD) of the spike trimer (S) constitute the two major neutralizing targets for antibodies. Here, we use NTD-specific probes to capture anti-NTD memory B cells in a longitudinal cohort of infected individuals, some of whom were vaccinated. We found 6 complementation groups of neutralizing antibodies. 58% targeted epitopes outside the NTD supersite, 58% neutralized either Gamma or Omicron, and 14% were broad neutralizers that also neutralized Omicron. Structural characterization revealed that broadly active antibodies targeted three epitopes outside the NTD supersite including a class that recognized both the NTD and SD2 domain. Rapid recruitment of memory B cells producing these antibodies into the plasma cell compartment upon re-infection likely contributes to the relatively benign course of subsequent infections with SARS-CoV-2 variants, including Omicron.
Collapse
Affiliation(s)
- Zijun Wang
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Frauke Muecksch
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA
| | - Alice Cho
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Christian Gaebler
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Hans-Heinrich Hoffmann
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Victor Ramos
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Shuai Zong
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Melissa Cipolla
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Briana Johnson
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Fabian Schmidt
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA
| | - Justin DaSilva
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA
| | - Eva Bednarski
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA
| | - Tarek Ben Tanfous
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Raphael Raspe
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Kaihui Yao
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Yu E Lee
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Teresia Chen
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Martina Turroja
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Katrina G Milard
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Juan Dizon
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Anna Kaczynska
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Anna Gazumyan
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Thiago Y Oliveira
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Charles M Rice
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Marina Caskey
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Paul D Bieniasz
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA.
| | | | - Christopher O Barnes
- Department of Biology, Stanford University, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
| | - Michel C Nussenzweig
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA.
| |
Collapse
|
30
|
Kar U, Khaleeq S, Garg P, Bhat M, Reddy P, Vignesh VS, Upadhyaya A, Das M, Chakshusmathi G, Pandey S, Dutta S, Varadarajan R. Comparative Immunogenicity of Bacterially Expressed Soluble Trimers and Nanoparticle Displayed Influenza Hemagglutinin Stem Immunogens. Front Immunol 2022; 13:890622. [PMID: 35720346 PMCID: PMC9204493 DOI: 10.3389/fimmu.2022.890622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 04/14/2022] [Indexed: 11/13/2022] Open
Abstract
Current influenza vaccines need to be updated annually due to mutations in the globular head of the viral surface protein, hemagglutinin (HA). To address this, vaccine candidates have been designed based on the relatively conserved HA stem domain and have shown protective efficacy in animal models. Oligomerization of the antigens either by fusion to oligomerization motifs or display on self-assembling nanoparticle scaffolds, can induce more potent immune responses compared to the corresponding monomeric antigen due to multivalent engagement of B-cells. Since nanoparticle display can increase manufacturing complexity, and often involves one or more mammalian cell expressed components, it is important to characterize and compare various display and oligomerization scaffolds. Using a structure guided approach, we successfully displayed multiple copies of a previously designed soluble, trimeric influenza stem domain immunogen, pH1HA10, on the ferritin like protein, MsDps2 (12 copies), Ferritin (24 copies) and Encapsulin (180 copies). All proteins were expressed in Escherichia coli. The nanoparticle fusion immunogens were found to be well folded and bound to the influenza stem directed broadly neutralizing antibodies with high affinity. An 8.5 Å Cryo-EM map of Msdps2-pH1HA10 confirmed the successful design of the nanoparticle fusion immunogen. Mice immunization studies with the soluble trimeric stem and nanoparticle fusion constructs revealed that all of them were immunogenic, and protected mice against homologous (A/Belgium/145-MA/2009) and heterologous (A/Puerto Rico/8/1934) challenge with 10MLD50 mouse adapted virus. Although nanoparticle display conferred a small but statistically significant improvement in protection relative to the soluble trimer in a homologous challenge, heterologous protection was similar in both nanoparticle-stem immunized and trimeric stem immunized groups. Such rapidly producible, bacterially expressed antigens and nanoparticle scaffolds are useful modalities to tackle future influenza pandemics.
Collapse
Affiliation(s)
- Uddipan Kar
- Molecular Biophysics Unit (MBU), Indian Institute of Science, Bengaluru, India
| | - Sara Khaleeq
- Molecular Biophysics Unit (MBU), Indian Institute of Science, Bengaluru, India
| | - Priyanka Garg
- Molecular Biophysics Unit (MBU), Indian Institute of Science, Bengaluru, India
| | - Madhuraj Bhat
- Mynvax Private Limited, ES12, Entrepreneurship Centre, Society for Innovation and Development (SID), Indian Institute of Science, Bengaluru, India
| | - Poorvi Reddy
- Mynvax Private Limited, ES12, Entrepreneurship Centre, Society for Innovation and Development (SID), Indian Institute of Science, Bengaluru, India
| | | | - Aditya Upadhyaya
- Mynvax Private Limited, ES12, Entrepreneurship Centre, Society for Innovation and Development (SID), Indian Institute of Science, Bengaluru, India
| | - Mili Das
- Mynvax Private Limited, ES12, Entrepreneurship Centre, Society for Innovation and Development (SID), Indian Institute of Science, Bengaluru, India
| | - Ghadiyaram Chakshusmathi
- Mynvax Private Limited, ES12, Entrepreneurship Centre, Society for Innovation and Development (SID), Indian Institute of Science, Bengaluru, India
| | - Suman Pandey
- Mynvax Private Limited, ES12, Entrepreneurship Centre, Society for Innovation and Development (SID), Indian Institute of Science, Bengaluru, India
| | - Somnath Dutta
- Molecular Biophysics Unit (MBU), Indian Institute of Science, Bengaluru, India
| | | |
Collapse
|
31
|
Kharel P, Janicek BE, Bae SH, Loutris AL, Carmichael PT, Huang PY. Atomic-Resolution Imaging of Small Organic Molecules on Graphene. NANO LETTERS 2022; 22:3628-3635. [PMID: 35413204 DOI: 10.1021/acs.nanolett.2c00213] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Here, we demonstrate atomic-resolution scanning transmission electron microscopy (STEM) imaging of light elements in small organic molecules on graphene. We use low-dose, room-temperature, aberration-corrected STEM to image 2D monolayer and bilayer molecular crystals, followed by advanced image processing methods to create high-quality composite images from ∼102-104 individual molecules. In metalated porphyrin and phthalocyanine derivatives, these images contain an elementally sensitive contrast with up to 1.3 Å resolution─sufficient to distinguish individual carbon and nitrogen atoms. Importantly, our methods can be applied to molecules with low masses (∼0.6 kDa) and nanocrystalline domains containing just a few hundred molecules, making it possible to study systems for which large crystals cannot easily be grown. Our approach is enabled by low-background graphene substrates, which we show increase the molecules' critical dose by 2-7×. These results indicate a new route for low-dose, atomic-resolution electron microscopy imaging to solve the structures of small organic molecules.
Collapse
Affiliation(s)
- Priti Kharel
- Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Blanka E Janicek
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Sang Hyun Bae
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Amanda L Loutris
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Patrick T Carmichael
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Pinshane Y Huang
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| |
Collapse
|
32
|
Iqbal T, Das D. Biochemical Investigation of Membrane-Bound Cytochrome b5 and the Catalytic Domain of Cytochrome b5 Reductase from Arabidopsis thaliana. Biochemistry 2022; 61:909-921. [PMID: 35475372 DOI: 10.1021/acs.biochem.2c00002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The endoplasmic reticulum (ER) membrane of plant cells contains several enzymes responsible for the biosynthesis of a diverse range of molecules essential for plant growth and holds potential for industrial applications. Many of these enzymes are dependent on electron transfer proteins to sustain their catalytic cycles. In plants, two crucial ER-bound electron transfer proteins are cytochrome b5 and cytochrome b5 reductase, which catalyze the stepwise transfer of electrons from NADH to redox enzymes such as fatty acid desaturases, cytochrome P450s, and plant aldehyde decarbonylase. Despite the high significance of plant cytochrome b5 and cytochrome b5 reductase, they have eluded detailed characterization to date. Here, we overexpressed the full-length membrane-bound cytochrome b5 isoform B from the model plant Arabidopsis thaliana in Escherichia coli, purified the protein employing detergents as well as styrene-maleic acid (SMA) copolymers, and biochemically characterized the protein. The SMA-encapsulated cytochrome b5 exhibits a discoidal shape and the characteristic features of the active heme-bound state. We also overexpressed and purified the soluble domain of cytochrome b5 reductase from A. thaliana, establishing its activity, stability, and kinetic parameters. Further, we demonstrated that the plant cytochrome b5, purified in detergents and styrene maleic acid lipid particles (SMALPs), readily accepts electrons from the cognate plant cytochrome b5 reductase and distant electron mediators such as plant NADPH-cytochrome P450 oxidoreductase and cyanobacterial NADPH-ferredoxin reductase. We also measured the kinetic parameters of cytochrome b5 reductase for cytochrome b5. Our studies are the first to report the purification and detailed biochemical characterization of the plant cytochrome b5 and cytochrome b5 reductase from the bacterial overexpression system.
Collapse
Affiliation(s)
- Tabish Iqbal
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Debasis Das
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, Karnataka 560012, India
| |
Collapse
|
33
|
3D reconstruction from cryo-EM projection images using two spherical embeddings. Commun Biol 2022; 5:304. [PMID: 35379919 PMCID: PMC8979997 DOI: 10.1038/s42003-022-03255-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 03/11/2022] [Indexed: 11/08/2022] Open
Abstract
Single-particle analysis (SPA) in cryo-electron microscopy has become a powerful tool for determining and studying the macromolecular structure at an atomic level. However, since the SPA problem is a non-convex optimization problem with enormous search space and there is high level of noise in the input images, the existing methods may produce biased or even wrong final models. In this work, to deal with the problem, consistent constraints from the input data are explored in an embedding space, a 3D spherical surface. More specifically, the orientation of a projection image is represented by two intersection points of the normal vector and the local X-axis vector of the projection image on the unit spherical surface. To determine the orientations of the projection images, the global consistency constraints of the relative orientations of all the projection images are satisfied by two spherical embeddings which estimate the normal vectors and the local X-axis vectors of the projection images respectively. Compared to the traditional methods, the proposed method is shown to be able to rectify the initial computation errors and produce a more accurate estimation of the projection angles, which results in a better final model reconstruction from the noisy image data. A 3D reconstruction method using two spherical embeddings to resolve projection angles of the cryo-EM images is shown to improve the initial model reconstruction for single-particle analysis.
Collapse
|
34
|
Chen C, Saville JW, Marti MM, Schäfer A, Cheng MH, Mannar D, Zhu X, Berezuk AM, Banerjee A, Sobolewski MD, Kim A, Treat BR, Da Silva Castanha PM, Enick N, McCormick KD, Liu X, Adams C, Hines MG, Sun Z, Chen W, Jacobs JL, Barratt-Boyes SM, Mellors JW, Baric RS, Bahar I, Dimitrov DS, Subramaniam S, Martinez DR, Li W. Potent Neutralization of Omicron and other SARS-CoV-2 Variants of Concern by Biparatopic Human VH Domains. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2022:2022.02.18.481058. [PMID: 35194603 PMCID: PMC8863138 DOI: 10.1101/2022.02.18.481058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The emergence of SARS-CoV-2 variants of concern (VOCs) requires the development of next-generation biologics that are effective against a variety of strains of the virus. Herein, we characterize a human V H domain, F6, which we generated by sequentially panning large phage displayed V H libraries against receptor binding domains (RBDs) containing VOC mutations. Cryo-EM analyses reveal that F6 has a unique binding mode that spans a broad surface of the RBD and involves the antibody framework region. Attachment of an Fc region to a fusion of F6 and ab8, a previously characterized V H domain, resulted in a construct (F6-ab8-Fc) that neutralized Omicron pseudoviruses with a half-maximal neutralizing concentration (IC 50 ) of 4.8 nM in vitro . Additionally, prophylactic treatment using F6-ab8-Fc reduced live Beta (B.1.351) variant viral titers in the lungs of a mouse model. Our results provide a new potential therapeutic against SARS-CoV-2 VOCs - including the recently emerged Omicron variant - and highlight a vulnerable epitope within the spike protein RBD that may be exploited to achieve broad protection against circulating variants.
Collapse
Affiliation(s)
- Chuan Chen
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical School, Pittsburgh, PA, USA
| | - James W. Saville
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver BC, V6T 1Z3
| | - Michelle M. Marti
- Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Alexandra Schäfer
- Department of Epidemiology, University of North Carolina at Chapel Hill, 135 Dauer Drive, 3109 Michael Hooker Research Center, Chapel Hill, NC 27599, USA
| | - Mary Hongying Cheng
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Dhiraj Mannar
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver BC, V6T 1Z3
| | - Xing Zhu
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver BC, V6T 1Z3
| | - Alison M. Berezuk
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver BC, V6T 1Z3
| | - Anupam Banerjee
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michele D. Sobolewski
- Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Andrew Kim
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical School, Pittsburgh, PA, USA
| | - Benjamin R. Treat
- Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Priscila Mayrelle Da Silva Castanha
- Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Nathan Enick
- Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Kevin D McCormick
- Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Xianglei Liu
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical School, Pittsburgh, PA, USA
| | - Cynthia Adams
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical School, Pittsburgh, PA, USA
| | - Margaret Grace Hines
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical School, Pittsburgh, PA, USA
| | - Zehua Sun
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical School, Pittsburgh, PA, USA
| | | | - Jana L. Jacobs
- Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Simon M. Barratt-Boyes
- Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - John W. Mellors
- Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America,Abound Bio, Pittsburgh, PA, USA
| | - Ralph S. Baric
- Department of Epidemiology, University of North Carolina at Chapel Hill, 135 Dauer Drive, 3109 Michael Hooker Research Center, Chapel Hill, NC 27599, USA
| | - Ivet Bahar
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Dimiter S. Dimitrov
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical School, Pittsburgh, PA, USA,Abound Bio, Pittsburgh, PA, USA,Correspondence: , , and
| | - Sriram Subramaniam
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver BC, V6T 1Z3,Correspondence: , , and
| | - David R. Martinez
- Department of Epidemiology, University of North Carolina at Chapel Hill, 135 Dauer Drive, 3109 Michael Hooker Research Center, Chapel Hill, NC 27599, USA,Correspondence: , , and
| | - Wei Li
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical School, Pittsburgh, PA, USA,Correspondence: , , and
| |
Collapse
|
35
|
Tanaka S, Olson CA, Barnes CO, Higashide W, Gonzalez M, Taft J, Richardson A, Martin-Fernandez M, Bogunovic D, Gnanapragasam PNP, Bjorkman PJ, Spilman P, Niazi K, Rabizadeh S, Soon-Shiong P. Rapid identification of neutralizing antibodies against SARS-CoV-2 variants by mRNA display. Cell Rep 2022; 38:110348. [PMID: 35114110 PMCID: PMC8769934 DOI: 10.1016/j.celrep.2022.110348] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 12/06/2021] [Accepted: 01/14/2022] [Indexed: 11/26/2022] Open
Abstract
The increasing prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with the ability to escape existing humoral protection conferred by previous infection and/or immunization necessitates the discovery of broadly reactive neutralizing antibodies (nAbs). Utilizing mRNA display, we identify a set of antibodies against SARS-CoV-2 spike (S) proteins and characterize the structures of nAbs that recognize epitopes in the S1 subunit of the S glycoprotein. These structural studies reveal distinct binding modes for several antibodies, including the targeting of rare cryptic epitopes in the receptor-binding domain (RBD) of S that interact with angiotensin-converting enzyme 2 (ACE2) to initiate infection, as well as the S1 subdomain 1. Further, we engineer a potent ACE2-blocking nAb to sustain binding to S RBD with the E484K and L452R substitutions found in multiple SARS-CoV-2 variants. We demonstrate that mRNA display is an approach for the rapid identification of nAbs that can be used in combination to combat emerging SARS-CoV-2 variants.
Collapse
Affiliation(s)
- Shiho Tanaka
- ImmunityBio, Inc., 9920 Jefferson Boulevard, Culver City, CA 90232, USA
| | - C Anders Olson
- ImmunityBio, Inc., 9920 Jefferson Boulevard, Culver City, CA 90232, USA.
| | - Christopher O Barnes
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Wendy Higashide
- ImmunityBio, Inc., 9920 Jefferson Boulevard, Culver City, CA 90232, USA
| | - Marcos Gonzalez
- ImmunityBio, Inc., 9920 Jefferson Boulevard, Culver City, CA 90232, USA
| | - Justin Taft
- Center for Inborn Errors of Immunity, Icahn School of Medicine at Mount Sinai, 1 Gustave Lane, Levy Plaza, New York, NY 10029-5674, USA; Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, 1 Gustave Lane, Levy Plaza, New York, NY 10029-5674, USA; Department of Microbiology, Icahn School of Medicine at Mount Sinai, 1 Gustave Lane, Levy Plaza, New York, NY 10029-5674, USA
| | - Ashley Richardson
- Center for Inborn Errors of Immunity, Icahn School of Medicine at Mount Sinai, 1 Gustave Lane, Levy Plaza, New York, NY 10029-5674, USA; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, 1 Gustave Lane, Levy Plaza, New York, NY 10029-5674, USA; Precision Immunology Institute, Icahn School of Medicine at Mount Sinai, 1 Gustave Lane, Levy Plaza, New York, NY 10029-5674, USA; Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, 1 Gustave Lane, Levy Plaza, New York, NY 10029-5674, USA; Department of Microbiology, Icahn School of Medicine at Mount Sinai, 1 Gustave Lane, Levy Plaza, New York, NY 10029-5674, USA
| | - Marta Martin-Fernandez
- Center for Inborn Errors of Immunity, Icahn School of Medicine at Mount Sinai, 1 Gustave Lane, Levy Plaza, New York, NY 10029-5674, USA; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, 1 Gustave Lane, Levy Plaza, New York, NY 10029-5674, USA; Precision Immunology Institute, Icahn School of Medicine at Mount Sinai, 1 Gustave Lane, Levy Plaza, New York, NY 10029-5674, USA; Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, 1 Gustave Lane, Levy Plaza, New York, NY 10029-5674, USA; Department of Microbiology, Icahn School of Medicine at Mount Sinai, 1 Gustave Lane, Levy Plaza, New York, NY 10029-5674, USA
| | - Dusan Bogunovic
- Center for Inborn Errors of Immunity, Icahn School of Medicine at Mount Sinai, 1 Gustave Lane, Levy Plaza, New York, NY 10029-5674, USA; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, 1 Gustave Lane, Levy Plaza, New York, NY 10029-5674, USA; Precision Immunology Institute, Icahn School of Medicine at Mount Sinai, 1 Gustave Lane, Levy Plaza, New York, NY 10029-5674, USA; Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, 1 Gustave Lane, Levy Plaza, New York, NY 10029-5674, USA; Department of Microbiology, Icahn School of Medicine at Mount Sinai, 1 Gustave Lane, Levy Plaza, New York, NY 10029-5674, USA
| | - Priyanthi N P Gnanapragasam
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Pamela J Bjorkman
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Patricia Spilman
- ImmunityBio, Inc., 9920 Jefferson Boulevard, Culver City, CA 90232, USA
| | - Kayvan Niazi
- ImmunityBio, Inc., 9920 Jefferson Boulevard, Culver City, CA 90232, USA
| | | | | |
Collapse
|
36
|
Saville JW, Mannar D, Zhu X, Srivastava SS, Berezuk AM, Demers JP, Zhou S, Tuttle KS, Sekirov I, Kim A, Li W, Dimitrov DS, Subramaniam S. Structural and biochemical rationale for enhanced spike protein fitness in delta and kappa SARS-CoV-2 variants. Nat Commun 2022; 13:742. [PMID: 35136050 PMCID: PMC8826856 DOI: 10.1038/s41467-022-28324-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 01/19/2022] [Indexed: 12/23/2022] Open
Abstract
The Delta and Kappa variants of SARS-CoV-2 co-emerged in India in late 2020, with the Delta variant underlying the resurgence of COVID-19, even in countries with high vaccination rates. In this study, we assess structural and biochemical aspects of viral fitness for these two variants using cryo-electron microscopy (cryo-EM), ACE2-binding and antibody neutralization analyses. Both variants demonstrate escape of antibodies targeting the N-terminal domain, an important immune hotspot for neutralizing epitopes. Compared to wild-type and Kappa lineages, Delta variant spike proteins show modest increase in ACE2 affinity, likely due to enhanced electrostatic complementarity at the RBD-ACE2 interface, which we characterize by cryo-EM. Unexpectedly, Kappa variant spike trimers form a structural head-to-head dimer-of-trimers assembly, which we demonstrate is a result of the E484Q mutation and with unknown biological implications. The combination of increased antibody escape and enhanced ACE2 binding provides an explanation, in part, for the rapid global dominance of the Delta variant.
Collapse
Affiliation(s)
- James W Saville
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Dhiraj Mannar
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Xing Zhu
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Shanti S Srivastava
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Alison M Berezuk
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Jean-Philippe Demers
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Steven Zhou
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Katharine S Tuttle
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Inna Sekirov
- BC Centre for Disease Control, Vancouver, BC, V5Z 4R4, Canada
| | - Andrew Kim
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, 3550 Terrace Str, Pittsburgh, PA, 15261, USA
| | - Wei Li
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, 3550 Terrace Str, Pittsburgh, PA, 15261, USA
| | - Dimiter S Dimitrov
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, 3550 Terrace Str, Pittsburgh, PA, 15261, USA
| | - Sriram Subramaniam
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
| |
Collapse
|
37
|
Wang Z, Muecksch F, Cho A, Gaebler C, Hoffmann HH, Ramos V, Zong S, Cipolla M, Johnson B, Schmidt F, DaSilva J, Bednarski E, Tanfous TB, Raspe R, Yao K, Lee YE, Chen T, Turroja M, Milard KG, Dizon J, Kaczynska A, Gazumyan A, Oliveira TY, Rice CM, Caskey M, Bieniasz PD, Hatziioannou T, Barnes CO, Nussenzweig MC. Conserved Neutralizing Epitopes on the N-Terminal Domain of Variant SARS-CoV-2 Spike Proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2022. [PMID: 35132412 PMCID: PMC8820657 DOI: 10.1101/2022.02.01.478695] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
SARS-CoV-2 infection or vaccination produces neutralizing antibody responses that contribute to better clinical outcomes. The receptor binding domain (RBD) and the N-terminal domain (NTD) of the spike trimer (S) constitute the two major neutralizing targets for the antibody system. Neutralizing antibodies targeting the RBD bind to several different sites on this domain. In contrast, most neutralizing antibodies to NTD characterized to date bind to a single supersite, however these antibodies were obtained by methods that were not NTD specific. Here we use NTD specific probes to focus on anti-NTD memory B cells in a cohort of pre-omicron infected individuals some of which were also vaccinated. Of 275 NTD binding antibodies tested 103 neutralized at least one of three tested strains: Wuhan-Hu-1, Gamma, or PMS20, a synthetic variant which is extensively mutated in the NTD supersite. Among the 43 neutralizing antibodies that were further characterized, we found 6 complementation groups based on competition binding experiments. 58% targeted epitopes outside the NTD supersite, and 58% neutralized either Gamma or Omicron, but only 14% were broad neutralizers. Three of the broad neutralizers were characterized structurally. C1520 and C1791 recognize epitopes on opposite faces of the NTD with a distinct binding pose relative to previously described antibodies allowing for greater potency and cross-reactivity with 7 different variants including Beta, Delta, Gamma and Omicron. Antibody C1717 represents a previously uncharacterized class of NTD-directed antibodies that recognizes the viral membrane proximal side of the NTD and SD2 domain, leading to cross-neutralization of Beta, Gamma and Omicron. We conclude SARS-CoV-2 infection and/or Wuhan-Hu-1 mRNA vaccination produces a diverse collection of memory B cells that produce anti-NTD antibodies some of which can neutralize variants of concern. Rapid recruitment of these cells into the antibody secreting plasma cell compartment upon re-infection likely contributes to the relatively benign course of subsequent infections with SARS-CoV-2 variants including omicron.
Collapse
Affiliation(s)
- Zijun Wang
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Frauke Muecksch
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA
| | - Alice Cho
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Christian Gaebler
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Hans-Heinrich Hoffmann
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Victor Ramos
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Shuai Zong
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Melissa Cipolla
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Briana Johnson
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Fabian Schmidt
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA
| | - Justin DaSilva
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA
| | - Eva Bednarski
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA
| | - Tarek Ben Tanfous
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Raphael Raspe
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Kaihui Yao
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Yu E Lee
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Teresia Chen
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Martina Turroja
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Katrina G Milard
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Juan Dizon
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Anna Kaczynska
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Anna Gazumyan
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Thiago Y Oliveira
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Charles M Rice
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Marina Caskey
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Paul D Bieniasz
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA.,Howard Hughes Medical Institute
| | | | - Christopher O Barnes
- Department of Biology, Stanford University, Stanford, CA 94305, USA.,Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | - Michel C Nussenzweig
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA.,Howard Hughes Medical Institute
| |
Collapse
|
38
|
Electron microscopy analysis of ATP-independent nucleosome unfolding by FACT. Commun Biol 2022; 5:2. [PMID: 35013515 PMCID: PMC8748794 DOI: 10.1038/s42003-021-02948-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 12/02/2021] [Indexed: 12/20/2022] Open
Abstract
FACT is a histone chaperone that participates in nucleosome removal and reassembly during transcription and replication. We used electron microscopy to study FACT, FACT:Nhp6 and FACT:Nhp6:nucleosome complexes, and found that all complexes adopt broad ranges of configurations, indicating high flexibility. We found unexpectedly that the DNA binding protein Nhp6 also binds to the C-terminal tails of FACT subunits, inducing more open geometries of FACT even in the absence of nucleosomes. Nhp6 therefore supports nucleosome unfolding by altering both the structure of FACT and the properties of nucleosomes. Complexes formed with FACT, Nhp6, and nucleosomes also produced a broad range of structures, revealing a large number of potential intermediates along a proposed unfolding pathway. The data suggest that Nhp6 has multiple roles before and during nucleosome unfolding by FACT, and that the process proceeds through a series of energetically similar intermediate structures, ultimately leading to an extensively unfolded form. Sivkina et al. present a biochemical and biophysical characterization of the interaction of S. cerevisiae histone chaperone FACT with the nucleosome core particle. They show that FACT adopts a more open geometry in the presence of Nhp6, and together they unfold nucleosomes to an almost extended conformation, suggesting a mechanism for FACT-facilitated disassembly of nucleosomes.
Collapse
|
39
|
Ahmed T, Nisler CR, Fluck EC, Walujkar S, Sotomayor M, Moiseenkova-Bell VY. Structure of the ancient TRPY1 channel from Saccharomyces cerevisiae reveals mechanisms of modulation by lipids and calcium. Structure 2022; 30:139-155.e5. [PMID: 34453887 PMCID: PMC8741645 DOI: 10.1016/j.str.2021.08.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/29/2021] [Accepted: 08/10/2021] [Indexed: 01/14/2023]
Abstract
Transient receptor potential (TRP) channels emerged in fungi as mechanosensitive osmoregulators. The Saccharomyces cerevisiae vacuolar TRP yeast 1 (TRPY1) is the most studied TRP channel from fungi, but the structure and details of channel modulation remain elusive. Here, we describe the full-length cryoelectron microscopy structure of TRPY1 at 3.1 Å resolution in a closed state. The structure, despite containing an evolutionarily conserved and archetypical transmembrane domain, reveals distinctive structural folds for the cytosolic N and C termini, compared with other eukaryotic TRP channels. We identify an inhibitory phosphatidylinositol 3-phosphate (PI(3)P) lipid-binding site, along with two Ca2+-binding sites: a cytosolic site, implicated in channel activation and a vacuolar lumen site, implicated in inhibition. These findings, together with data from microsecond-long molecular dynamics simulations and a model of a TRPY1 open state, provide insights into the basis of TRPY1 channel modulation by lipids and Ca2+, and the molecular evolution of TRP channels.
Collapse
Affiliation(s)
- Tofayel Ahmed
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Collin R Nisler
- Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210, USA; Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Edwin C Fluck
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sanket Walujkar
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; Chemical Physics Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Marcos Sotomayor
- Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210, USA; Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; Chemical Physics Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Vera Y Moiseenkova-Bell
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| |
Collapse
|
40
|
Structural analysis of receptor binding domain mutations in SARS-CoV-2 variants of concern that modulate ACE2 and antibody binding. Cell Rep 2021; 37:110156. [PMID: 34914928 PMCID: PMC8642162 DOI: 10.1016/j.celrep.2021.110156] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 10/20/2021] [Accepted: 12/01/2021] [Indexed: 12/25/2022] Open
Abstract
The recently emerged severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) Beta (B.1.351) and Gamma (P.1) variants of concern (VoCs) include a key mutation (N501Y) found in the Alpha (B.1.1.7) variant that enhances affinity of the spike protein for its receptor, angiotensin-converting enzyme 2 (ACE2). Additional mutations are found in these variants at residues 417 and 484 that appear to promote antibody evasion. In contrast, the Epsilon variants (B.1.427/429) lack the N501Y mutation yet exhibit antibody evasion. We have engineered spike proteins to express these receptor binding domain (RBD) VoC mutations either in isolation or in different combinations and analyze the effects using biochemical assays and cryoelectron microscopy (cryo-EM) structural analyses. Overall, our findings suggest that the emergence of new SARS-CoV-2 variant spikes can be rationalized as the result of mutations that confer increased ACE2 affinity, increased antibody evasion, or both, providing a framework to dissect the molecular factors that drive VoC evolution.
Collapse
|
41
|
Arimura Y, Shih RM, Froom R, Funabiki H. Structural features of nucleosomes in interphase and metaphase chromosomes. Mol Cell 2021; 81:4377-4397.e12. [PMID: 34478647 PMCID: PMC8571072 DOI: 10.1016/j.molcel.2021.08.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 08/05/2021] [Accepted: 08/06/2021] [Indexed: 12/17/2022]
Abstract
Structural heterogeneity of nucleosomes in functional chromosomes is unknown. Here, we devise the template-, reference- and selection-free (TRSF) cryo-EM pipeline to simultaneously reconstruct cryo-EM structures of protein complexes from interphase or metaphase chromosomes. The reconstructed interphase and metaphase nucleosome structures are on average indistinguishable from canonical nucleosome structures, despite DNA sequence heterogeneity, cell-cycle-specific posttranslational modifications, and interacting proteins. Nucleosome structures determined by a decoy-classifying method and structure variability analyses reveal the nucleosome structural variations in linker DNA, histone tails, and nucleosome core particle configurations, suggesting that the opening of linker DNA, which is correlated with H2A C-terminal tail positioning, is suppressed in chromosomes. High-resolution (3.4-3.5 Å) nucleosome structures indicate DNA-sequence-independent stabilization of superhelical locations ±0-1 and ±3.5-4.5. The linker histone H1.8 preferentially binds to metaphase chromatin, from which chromatosome cryo-EM structures with H1.8 at the on-dyad position are reconstituted. This study presents the structural characteristics of nucleosomes in chromosomes.
Collapse
Affiliation(s)
- Yasuhiro Arimura
- Laboratory of Chromosome and Cell Biology, The Rockefeller University, New York, NY 10065, USA.
| | - Rochelle M Shih
- Laboratory of Chromosome and Cell Biology, The Rockefeller University, New York, NY 10065, USA
| | - Ruby Froom
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Hironori Funabiki
- Laboratory of Chromosome and Cell Biology, The Rockefeller University, New York, NY 10065, USA.
| |
Collapse
|
42
|
Multiple nanocages of a cyanophage small heat shock protein with icosahedral and octahedral symmetries. Sci Rep 2021; 11:21023. [PMID: 34697325 PMCID: PMC8546028 DOI: 10.1038/s41598-021-00172-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Accepted: 09/28/2021] [Indexed: 11/08/2022] Open
Abstract
The structures of a cyanophage small heat shock protein (sHSP) were determined as octahedrons of 24-mers and 48-mers and as icosahedrons of 60-mers. An N-terminal deletion construct of an 18 kDa sHSP of Synechococcus sp. phage S-ShM2 crystallized as a 24-mer and its structure was determined at a resolution of 7 Å. The negative stain electron microscopy (EM) images showed that the full-length protein is a mixture of a major population of larger and a minor population of smaller cage-like particles. Their structures have been determined by electron cryomicroscopy 3D image reconstruction at a resolution of 8 Å. The larger particles are 60-mers with icosahedral symmetry and the smaller ones are 48-mers with octahedral symmetry. These structures are the first of the viral/phage origin and the 60-mer is the largest and the first icosahedral assembly to be reported for sHSPs.
Collapse
|
43
|
Jette CA, Cohen AA, Gnanapragasam PNP, Muecksch F, Lee YE, Huey-Tubman KE, Schmidt F, Hatziioannou T, Bieniasz PD, Nussenzweig MC, West AP, Keeffe JR, Bjorkman PJ, Barnes CO. Broad cross-reactivity across sarbecoviruses exhibited by a subset of COVID-19 donor-derived neutralizing antibodies. Cell Rep 2021; 36:109760. [PMID: 34534459 PMCID: PMC8423902 DOI: 10.1016/j.celrep.2021.109760] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 08/05/2021] [Accepted: 09/01/2021] [Indexed: 01/21/2023] Open
Abstract
Many anti-severe acute respiratory syndrome coronavirus 2 (anti-SARS-CoV-2) neutralizing antibodies target the angiotensin-converting enzyme 2 (ACE2) binding site on viral spike receptor-binding domains (RBDs). Potent antibodies recognize exposed variable epitopes, often rendering them ineffective against other sarbecoviruses and SARS-CoV-2 variants. Class 4 anti-RBD antibodies against a less-exposed, but more-conserved, cryptic epitope could recognize newly emergent zoonotic sarbecoviruses and variants, but they usually show only weak neutralization potencies. Here, we characterize two class 4 anti-RBD antibodies derived from coronavirus disease 2019 (COVID-19) donors that exhibit breadth and potent neutralization of zoonotic coronaviruses and SARS-CoV-2 variants. C118-RBD and C022-RBD structures reveal orientations that extend from the cryptic epitope to occlude ACE2 binding and CDRH3-RBD main-chain H-bond interactions that extend an RBD β sheet, thus reducing sensitivity to RBD side-chain changes. A C118-spike trimer structure reveals rotated RBDs that allow access to the cryptic epitope and the potential for intra-spike crosslinking to increase avidity. These studies facilitate vaccine design and illustrate potential advantages of class 4 RBD-binding antibody therapeutics.
Collapse
Affiliation(s)
- Claudia A Jette
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Alexander A Cohen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | | | - Frauke Muecksch
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA
| | - Yu E Lee
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Kathryn E Huey-Tubman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Fabian Schmidt
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA
| | | | - Paul D Bieniasz
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA; Howard Hughes Medical Institute
| | - Michel C Nussenzweig
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA; Howard Hughes Medical Institute
| | - Anthony P West
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Jennifer R Keeffe
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Pamela J Bjorkman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Christopher O Barnes
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
| |
Collapse
|
44
|
Tanaka S, Anders Olson C, Barnes CO, Higashide W, Gonzalez M, Taft J, Richardson A, Martin-Fernandez M, Bogunovic D, Gnanapragasam PNP, Bjorkman PJ, Spilman P, Niazi K, Rabizadeh S, Soon-Shiong P. Rapid Identification of Neutralizing Antibodies against SARS-CoV-2 Variants by mRNA Display. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021:2021.09.14.460356. [PMID: 34545362 PMCID: PMC8452091 DOI: 10.1101/2021.09.14.460356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The increasing prevalence of SARS-CoV-2 variants with the ability to escape existing humoral protection conferred by previous infection and/or immunization necessitates the discovery of broadly-reactive neutralizing antibodies (nAbs). Utilizing mRNA display, we identified a set of antibodies against SARS-CoV-2 spike (S) proteins and characterized the structures of nAbs that recognized epitopes in the S1 subunit of the S glycoprotein. These structural studies revealed distinct binding modes for several antibodies, including targeting of rare cryptic epitopes in the receptor-binding domain (RBD) of S that interacts with angiotensin- converting enzyme 2 (ACE2) to initiate infection, as well as the S1 subdomain 1. A potent ACE2-blocking nAb was further engineered to sustain binding to S RBD with the E484K and L452R substitutions found in multiple SARS-CoV-2 variants. We demonstrate that mRNA display is a promising approach for the rapid identification of nAbs that can be used in combination to combat emerging SARS-CoV-2 variants.
Collapse
|
45
|
Pintilie G, Chiu W. Validation, analysis and annotation of cryo-EM structures. Acta Crystallogr D Struct Biol 2021; 77:1142-1152. [PMID: 34473085 PMCID: PMC8411978 DOI: 10.1107/s2059798321006069] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 06/09/2021] [Indexed: 11/08/2023] Open
Abstract
The process of turning 2D micrographs into 3D atomic models of the imaged macromolecules has been under rapid development and scrutiny in the field of cryo-EM. Here, some important methods for validation at several stages in this process are described. Firstly, how Fourier shell correlation of two independent maps and phase randomization beyond a certain frequency address the assessment of map resolution is reviewed. Techniques for local resolution estimation and map sharpening are also touched upon. The topic of validating models which are either built de novo or based on a known atomic structure fitted into a cryo-EM map is then approached. Map-model comparison using Q-scores and Fourier shell correlation plots is used to assure the agreement of the model with the observed map density. The importance of annotating the model with B factors to account for the resolvability of individual atoms in the map is illustrated. Finally, the timely topic of detecting and validating water molecules and metal ions in maps that have surpassed ∼2 Å resolution is described.
Collapse
Affiliation(s)
- Grigore Pintilie
- Department of Bioengineering, James H. Clark Center, Stanford University, Stanford, CA 94305, USA
| | - Wah Chiu
- Department of Bioengineering, James H. Clark Center, Stanford University, Stanford, CA 94305, USA
- Division of Cryo-EM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, USA
| |
Collapse
|
46
|
Abstract
In the recent years, the protein databank has been fueled by the exponential growth of high-resolution electron cryo-microscopy (cryo-EM) structures. This trend will be further accelerated through the continuous software and method developments and the increasing availability of imaging centers, which will open cryo-EM to a wide array of researchers with their diverse scientific goals and questions. Especially for structural biology of membrane proteins, cryo-EM offers significant advantages as it can overcome multiple limitations of classical methods. Most importantly, in cryo-EM, the sample is prepared as a vitrified suspension, which abolishes the need for crystallization, reduces the required sample amount and allows usage of a wide arsenal of hydrophobic environments. Despite recent improvements, high-resolution cryo-EM still poses some significant challenges, and standardized procedures, especially for the characterization of membrane proteins, are missing. While there can be no ultimate recipe toward a high-resolution cryo-EM structure for every membrane protein, certain factors seem to be universally relevant. Here, we share the protocols that have been successfully used in our laboratory. We hope that this may be a useful resource to other researchers in the field and may increase their chances of success.
Collapse
Affiliation(s)
- Dovile Januliene
- Max-Planck Institute of Biophysics, Frankfurt, Germany.,Department of Structural Biology, University of Osnabrück, Osnabrück, Germany
| | - Arne Moeller
- Max-Planck Institute of Biophysics, Frankfurt, Germany. .,Department of Structural Biology, University of Osnabrück, Osnabrück, Germany.
| |
Collapse
|
47
|
Chen M, Ludtke SJ. Deep learning-based mixed-dimensional Gaussian mixture model for characterizing variability in cryo-EM. Nat Methods 2021; 18:930-936. [PMID: 34326541 PMCID: PMC8363932 DOI: 10.1038/s41592-021-01220-5] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 06/21/2021] [Indexed: 12/15/2022]
Abstract
Structural flexibility and/or dynamic interactions with other molecules is a critical aspect of protein function. CryoEM provides direct visualization of individual macromolecules sampling different conformational and compositional states. While numerous methods are available for computational classification of discrete states, characterization of continuous conformational changes or large numbers of discrete state without human supervision remains challenging. Here we present e2gmm, a machine learning algorithm to determine a conformational landscape for proteins or complexes using a 3-D Gaussian mixture model mapped onto 2-D particle images in known orientations. Using a deep neural network architecture, e2gmm can automatically resolve the structural heterogeneity within the protein complex and map particles onto a small latent space describing conformational and compositional changes. This system presents a more intuitive and flexible representation than other manifold methods currently in use. We demonstrate this method on both simulated data as well as three biological systems, to explore compositional and conformational changes at a range of scales. The software is distributed as part of EMAN2.
Collapse
Affiliation(s)
- Muyuan Chen
- Verna Marrs and McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Steven J Ludtke
- Verna Marrs and McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA.
| |
Collapse
|
48
|
Cremers GAO, Rosier BJHM, Meijs A, Tito NB, van Duijnhoven SMJ, van Eenennaam H, Albertazzi L, de Greef TFA. Determinants of Ligand-Functionalized DNA Nanostructure-Cell Interactions. J Am Chem Soc 2021; 143:10131-10142. [PMID: 34180666 PMCID: PMC8283757 DOI: 10.1021/jacs.1c02298] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
![]()
Synthesis of ligand-functionalized
nanomaterials with control over
size, shape, and ligand orientation facilitates the design of targeted
nanomedicines for therapeutic purposes. DNA nanotechnology has emerged
as a powerful tool to rationally construct two- and three-dimensional
nanostructures, enabling site-specific incorporation of protein ligands
with control over stoichiometry and orientation. To efficiently target
cell surface receptors, exploration of the parameters that modulate
cellular accessibility of these nanostructures is essential. In this
study, we systematically investigate tunable design parameters of
antibody-functionalized DNA nanostructures binding to therapeutically
relevant receptors, including the programmed cell death protein 1,
the epidermal growth factor receptor, and the human epidermal growth
factor receptor 2. We show that, although the native affinity of antibody-functionalized
DNA nanostructures remains unaltered, the absolute number of bound
surface receptors is lower compared to soluble antibodies due to receptor
accessibility by the nanostructure. We explore structural determinants
of this phenomenon to improve efficiency, revealing that receptor
binding is mainly governed by nanostructure size and DNA handle location.
The obtained results provide key insights in the ability of ligand-functionalized
DNA nanostructures to bind surface receptors and yields design rules
for optimal cellular targeting.
Collapse
Affiliation(s)
- Glenn A O Cremers
- Laboratory of Chemical Biology and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.,Computational Biology Group, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Bas J H M Rosier
- Laboratory of Chemical Biology and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.,Computational Biology Group, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Ab Meijs
- Laboratory of Chemical Biology and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.,Computational Biology Group, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.,Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Nicholas B Tito
- Electric Ant Lab, Science Park 106, 1098 XG Amsterdam, The Netherlands
| | | | - Hans van Eenennaam
- Aduro Biotech Europe B.V., Kloosterstraat 9, 5349 AB Oss, The Netherlands
| | - Lorenzo Albertazzi
- Laboratory of Chemical Biology and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.,Molecular Biosensing for Medical Diagnostics, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Tom F A de Greef
- Laboratory of Chemical Biology and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.,Computational Biology Group, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.,Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.,Center for Living Technologies, Eindhoven-Wageningen-Utrecht Alliance, 5600 MB Eindhoven, The Netherlands
| |
Collapse
|
49
|
Vanden Broeck A, Lotz C, Drillien R, Haas L, Bedez C, Lamour V. Structural basis for allosteric regulation of Human Topoisomerase IIα. Nat Commun 2021; 12:2962. [PMID: 34016969 PMCID: PMC8137924 DOI: 10.1038/s41467-021-23136-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 04/15/2021] [Indexed: 12/01/2022] Open
Abstract
The human type IIA topoisomerases (Top2) are essential enzymes that regulate DNA topology and chromosome organization. The Topo IIα isoform is a prime target for antineoplastic compounds used in cancer therapy that form ternary cleavage complexes with the DNA. Despite extensive studies, structural information on this large dimeric assembly is limited to the catalytic domains, hindering the exploration of allosteric mechanism governing the enzyme activities and the contribution of its non-conserved C-terminal domain (CTD). Herein we present cryo-EM structures of the entire human Topo IIα nucleoprotein complex in different conformations solved at subnanometer resolutions (3.6-7.4 Å). Our data unveils the molecular determinants that fine tune the allosteric connections between the ATPase domain and the DNA binding/cleavage domain. Strikingly, the reconstruction of the DNA-binding/cleavage domain uncovers a linker leading to the CTD, which plays a critical role in modulating the enzyme's activities and opens perspective for the analysis of post-translational modifications.
Collapse
Affiliation(s)
- Arnaud Vanden Broeck
- Université de Strasbourg, CNRS, INSERM, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Department of Integrated Structural Biology, IGBMC, Illkirch, France
| | - Christophe Lotz
- Université de Strasbourg, CNRS, INSERM, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Department of Integrated Structural Biology, IGBMC, Illkirch, France
| | - Robert Drillien
- Université de Strasbourg, CNRS, INSERM, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Department of Integrated Structural Biology, IGBMC, Illkirch, France
| | - Léa Haas
- Université de Strasbourg, CNRS, INSERM, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Department of Integrated Structural Biology, IGBMC, Illkirch, France
| | - Claire Bedez
- Université de Strasbourg, CNRS, INSERM, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Department of Integrated Structural Biology, IGBMC, Illkirch, France
| | - Valérie Lamour
- Université de Strasbourg, CNRS, INSERM, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.
- Department of Integrated Structural Biology, IGBMC, Illkirch, France.
- Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
| |
Collapse
|
50
|
Jette CA, Cohen AA, Gnanapragasam PN, Muecksch F, Lee YE, Huey-Tubman KE, Schmidt F, Hatziioannou T, Bieniasz PD, Nussenzweig MC, West AP, Keeffe JR, Bjorkman PJ, Barnes CO. Broad cross-reactivity across sarbecoviruses exhibited by a subset of COVID-19 donor-derived neutralizing antibodies. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021:2021.04.23.441195. [PMID: 33948592 PMCID: PMC8095199 DOI: 10.1101/2021.04.23.441195] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Many anti-SARS-CoV-2 neutralizing antibodies target the ACE2-binding site on viral spike receptor-binding domains (RBDs). The most potent antibodies recognize exposed variable epitopes, often rendering them ineffective against other sarbecoviruses and SARS-CoV-2 variants. Class 4 anti-RBD antibodies against a less-exposed, but more-conserved, cryptic epitope could recognize newly-emergent zoonotic sarbecoviruses and variants, but usually show only weak neutralization potencies. We characterized two class 4 anti-RBD antibodies derived from COVID-19 donors that exhibited broad recognition and potent neutralization of zoonotic coronavirus and SARS-CoV-2 variants. C118-RBD and C022-RBD structures revealed CDRH3 mainchain H-bond interactions that extended an RBD β-sheet, thus reducing sensitivity to RBD sidechain changes, and epitopes that extended from the cryptic epitope to occlude ACE2 binding. A C118-spike trimer structure revealed rotated RBDs to allow cryptic epitope access and the potential for intra-spike crosslinking to increase avidity. These studies facilitate vaccine design and illustrate potential advantages of class 4 RBD-binding antibody therapeutics.
Collapse
Affiliation(s)
- Claudia A. Jette
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Alexander A. Cohen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | | | - Frauke Muecksch
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065
| | - Yu E. Lee
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Kathryn E. Huey-Tubman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Fabian Schmidt
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065
| | | | - Paul D. Bieniasz
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065
- Howard Hughes Medical Institute
| | - Michel C. Nussenzweig
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065
- Howard Hughes Medical Institute
| | - Anthony P. West
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Jennifer R. Keeffe
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Pamela J. Bjorkman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Christopher O. Barnes
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| |
Collapse
|