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Chua GNL, Watters JW, Olinares PDB, Begum M, Vostal LE, Luo JA, Chait BT, Liu S. Differential dynamics specify MeCP2 function at nucleosomes and methylated DNA. Nat Struct Mol Biol 2024:10.1038/s41594-024-01373-9. [PMID: 39164525 DOI: 10.1038/s41594-024-01373-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 07/16/2024] [Indexed: 08/22/2024]
Abstract
Methyl-CpG-binding protein 2 (MeCP2) is an essential chromatin-binding protein whose mutations cause Rett syndrome (RTT), a severe neurological disorder that primarily affects young females. The canonical view of MeCP2 as a DNA methylation-dependent transcriptional repressor has proven insufficient to describe its dynamic interaction with chromatin and multifaceted roles in genome organization and gene expression. Here we used single-molecule correlative force and fluorescence microscopy to directly visualize the dynamics of wild-type and RTT-causing mutant MeCP2 on DNA. We discovered that MeCP2 exhibits distinct one-dimensional diffusion kinetics when bound to unmethylated versus CpG methylated DNA, enabling methylation-specific activities such as co-repressor recruitment. We further found that, on chromatinized DNA, MeCP2 preferentially localizes to nucleosomes and stabilizes them from mechanical perturbation. Our results reveal the multimodal behavior of MeCP2 on chromatin that underlies its DNA methylation- and nucleosome-dependent functions and provide a biophysical framework for dissecting the molecular pathology of RTT mutations.
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Affiliation(s)
- Gabriella N L Chua
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
- Tri-Institutional PhD Program in Chemical Biology, New York, NY, USA
| | - John W Watters
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Masuda Begum
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Lauren E Vostal
- Tri-Institutional PhD Program in Chemical Biology, New York, NY, USA
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY, USA
| | - Joshua A Luo
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Shixin Liu
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA.
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2
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Small GI, Fedorova O, Olinares PDB, Chandanani J, Banerjee A, Choi YJ, Molina H, Chait BT, Darst SA, Campbell EA. Structural and functional insights into the enzymatic plasticity of the SARS-CoV-2 NiRAN domain. Mol Cell 2023; 83:3921-3930.e7. [PMID: 37890482 PMCID: PMC10843261 DOI: 10.1016/j.molcel.2023.10.001] [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: 06/07/2023] [Revised: 08/28/2023] [Accepted: 10/03/2023] [Indexed: 10/29/2023]
Abstract
The enzymatic activity of the SARS-CoV-2 nidovirus RdRp-associated nucleotidyltransferase (NiRAN) domain is essential for viral propagation, with three distinct activities associated with modification of the nsp9 N terminus, NMPylation, RNAylation, and deRNAylation/capping via a GDP-polyribonucleotidyltransferase reaction. The latter two activities comprise an unconventional mechanism for initiating viral RNA 5' cap formation, while the role of NMPylation is unclear. The structural mechanisms for these diverse enzymatic activities have not been properly delineated. Here, we determine high-resolution cryoelectron microscopy (cryo-EM) structures of catalytic intermediates for the NMPylation and deRNAylation/capping reactions, revealing diverse nucleotide binding poses and divalent metal ion coordination sites to promote its repertoire of activities. The deRNAylation/capping structure explains why GDP is a preferred substrate for the capping reaction over GTP. Altogether, these findings enhance our understanding of the promiscuous coronaviral NiRAN domain, a therapeutic target, and provide an accurate structural platform for drug development.
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Affiliation(s)
- Gabriel I Small
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Olga Fedorova
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA
| | - Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Joshua Chandanani
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Anoosha Banerjee
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA; Tri-Institutional Program in Chemical Biology, The Rockefeller University, New York, New York, USA
| | - Young Joo Choi
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Henrik Molina
- Proteomics Resource Center, The Rockefeller University, New York, NY 10065, USA
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Seth A Darst
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
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3
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Small GI, Fedorova O, Olinares PDB, Chandanani J, Banerjee A, Choi YJ, Molina H, Chait B, Darst SA, Campbell EA. Structural and functional insights into the enzymatic plasticity of the SARS-CoV-2 NiRAN Domain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.25.558837. [PMID: 37808858 PMCID: PMC10557602 DOI: 10.1101/2023.09.25.558837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
The enzymatic activity of the SARS-CoV-2 nidovirus RdRp-associated nucleotidyltransferase (NiRAN) domain is essential for viral propagation, with three distinct activities associated with modification of the nsp9 N-terminus, NMPylation, RNAylation, and deRNAylation/capping via a GDP-polyribonucleotidyltransferase reaction. The latter two activities comprise an unconventional mechanism for initiating viral RNA 5'-cap formation, while the role of NMPylation is unclear. The structural mechanisms for these diverse enzymatic activities have not been properly delineated. Here we determine high-resolution cryo-electron microscopy structures of catalytic intermediates for the NMPylation and deRNAylation/capping reactions, revealing diverse nucleotide binding poses and divalent metal ion coordination sites to promote its repertoire of activities. The deRNAylation/capping structure explains why GDP is a preferred substrate for the capping reaction over GTP. Altogether, these findings enhance our understanding of the promiscuous coronaviral NiRAN domain, a therapeutic target, and provide an accurate structural platform for drug development.
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Affiliation(s)
- Gabriel I Small
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Olga Fedorova
- Department of Chemistry and Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
- Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA
| | - Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Joshua Chandanani
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Anoosha Banerjee
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Young Joo Choi
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
- Present address: University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
| | - Henrik Molina
- Proteomics Resource Center, The Rockefeller University, New York, NY 10065, USA
| | - Brian Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Seth A Darst
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
- Lead contact:
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4
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Chua GNL, Watters JW, Olinares PDB, Luo JA, Chait BT, Liu S. Differential dynamics specify MeCP2 function at methylated DNA and nucleosomes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.02.543478. [PMID: 37333354 PMCID: PMC10274721 DOI: 10.1101/2023.06.02.543478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Methyl-CpG-binding protein 2 (MeCP2) is an essential chromatin-binding protein whose mutations cause Rett syndrome (RTT), a leading cause of monogenic intellectual disabilities in females. Despite its significant biomedical relevance, the mechanism by which MeCP2 navigates the chromatin epigenetic landscape to regulate chromatin structure and gene expression remains unclear. Here, we used correlative single-molecule fluorescence and force microscopy to directly visualize the distribution and dynamics of MeCP2 on a variety of DNA and chromatin substrates. We found that MeCP2 exhibits differential diffusion dynamics when bound to unmethylated and methylated bare DNA. Moreover, we discovered that MeCP2 preferentially binds nucleosomes within the context of chromatinized DNA and stabilizes them from mechanical perturbation. The distinct behaviors of MeCP2 at bare DNA and nucleosomes also specify its ability to recruit TBLR1, a core component of the NCoR1/2 co-repressor complex. We further examined several RTT mutations and found that they disrupt different aspects of the MeCP2-chromatin interaction, rationalizing the heterogeneous nature of the disease. Our work reveals the biophysical basis for MeCP2's methylation-dependent activities and suggests a nucleosome-centric model for its genomic distribution and gene repressive functions. These insights provide a framework for delineating the multifaceted functions of MeCP2 and aid in our understanding of the molecular mechanisms of RTT.
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Affiliation(s)
- Gabriella N. L. Chua
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
- Tri-Institutional PhD Program in Chemical Biology, New York, NY, USA
| | - John W. Watters
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Paul Dominic B. Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Joshua A. Luo
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Brian T. Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Shixin Liu
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
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5
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Malone BF, Perry JK, Olinares PDB, Lee HW, Chen J, Appleby TC, Feng JY, Bilello JP, Ng H, Sotiris J, Ebrahim M, Chua EYD, Mendez JH, Eng ET, Landick R, Götte M, Chait BT, Campbell EA, Darst SA. Structural basis for substrate selection by the SARS-CoV-2 replicase. Nature 2023; 614:781-787. [PMID: 36725929 PMCID: PMC9891196 DOI: 10.1038/s41586-022-05664-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 12/15/2022] [Indexed: 02/03/2023]
Abstract
The SARS-CoV-2 RNA-dependent RNA polymerase coordinates viral RNA synthesis as part of an assembly known as the replication-transcription complex (RTC)1. Accordingly, the RTC is a target for clinically approved antiviral nucleoside analogues, including remdesivir2. Faithful synthesis of viral RNAs by the RTC requires recognition of the correct nucleotide triphosphate (NTP) for incorporation into the nascent RNA. To be effective inhibitors, antiviral nucleoside analogues must compete with the natural NTPs for incorporation. How the SARS-CoV-2 RTC discriminates between the natural NTPs, and how antiviral nucleoside analogues compete, has not been discerned in detail. Here, we use cryogenic-electron microscopy to visualize the RTC bound to each of the natural NTPs in states poised for incorporation. Furthermore, we investigate the RTC with the active metabolite of remdesivir, remdesivir triphosphate (RDV-TP), highlighting the structural basis for the selective incorporation of RDV-TP over its natural counterpart adenosine triphosphate3,4. Our results explain the suite of interactions required for NTP recognition, informing the rational design of antivirals. Our analysis also yields insights into nucleotide recognition by the nsp12 NiRAN (nidovirus RdRp-associated nucleotidyltransferase), an enigmatic catalytic domain essential for viral propagation5. The NiRAN selectively binds guanosine triphosphate, strengthening proposals for the role of this domain in the formation of the 5' RNA cap6.
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Affiliation(s)
- Brandon F Malone
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA
| | | | - Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Hery W Lee
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - James Chen
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA
- Department of Cell Biology, New York University School of Medicine, New York, NY, USA
| | | | - Joy Y Feng
- Gilead Sciences, Inc., Foster City, CA, USA
| | | | - Honkit Ng
- The Evelyn Gruss Lipper Cryo-Electron Microscopy Resource Center, The Rockefeller University, New York, NY, USA
| | - Johanna Sotiris
- The Evelyn Gruss Lipper Cryo-Electron Microscopy Resource Center, The Rockefeller University, New York, NY, USA
| | - Mark Ebrahim
- The Evelyn Gruss Lipper Cryo-Electron Microscopy Resource Center, The Rockefeller University, New York, NY, USA
| | - Eugene Y D Chua
- National Center for Cryo-EM Access and Training, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Joshua H Mendez
- National Center for Cryo-EM Access and Training, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Ed T Eng
- National Center for Cryo-EM Access and Training, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Matthias Götte
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA.
| | - Seth A Darst
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA.
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6
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Berman AY, Wieczorek M, Aher A, Olinares PDB, Chait BT, Kapoor TM. A nucleotide binding-independent role for γ-tubulin in microtubule capping and cell division. J Cell Biol 2023; 222:213828. [PMID: 36695784 PMCID: PMC9930161 DOI: 10.1083/jcb.202204102] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 10/20/2022] [Accepted: 12/22/2022] [Indexed: 01/26/2023] Open
Abstract
The γ-tubulin ring complex (γ-TuRC) has essential roles in centrosomal and non-centrosomal microtubule organization during vertebrate mitosis. While there have been important advances in understanding γ-TuRC-dependent microtubule nucleation, γ-TuRC capping of microtubule minus-ends remains poorly characterized. Here, we utilized biochemical reconstitutions and cellular assays to characterize the human γ-TuRC's capping activity. Single filament assays showed that the γ-TuRC remained associated with a nucleated microtubule for tens of minutes. In contrast, caps at dynamic microtubule minus-ends displayed lifetimes of ∼1 min. Reconstituted γ-TuRCs with nucleotide-binding deficient γ-tubulin (γ-tubulinΔGTP) formed ring-shaped complexes that did not nucleate microtubules but capped microtubule minus-ends with lifetimes similar to those measured for wild-type complexes. In dividing cells, microtubule regrowth assays revealed that while knockdown of γ-tubulin suppressed non-centrosomal microtubule formation, add-back of γ-tubulinΔGTP could substantially restore this process. Our results suggest that γ-TuRC capping is a nucleotide-binding-independent activity that plays a role in non-centrosomal microtubule organization during cell division.
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Affiliation(s)
- Adi Y. Berman
- https://ror.org/0420db125Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY, USA,Tri-Institutional PhD Program in Chemical Biology, The Rockefeller University, New York, NY, USA
| | - Michal Wieczorek
- https://ror.org/0420db125Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY, USA
| | - Amol Aher
- https://ror.org/0420db125Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY, USA
| | - Paul Dominic B. Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Brian T. Chait
- Tri-Institutional PhD Program in Chemical Biology, The Rockefeller University, New York, NY, USA,Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Tarun M. Kapoor
- https://ror.org/0420db125Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY, USA,Tri-Institutional PhD Program in Chemical Biology, The Rockefeller University, New York, NY, USA
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7
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Structural basis of transcriptional regulation by a nascent RNA element, HK022 putRNA. Nat Commun 2022; 13:4668. [PMID: 35970830 PMCID: PMC9378689 DOI: 10.1038/s41467-022-32315-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 07/26/2022] [Indexed: 12/16/2022] Open
Abstract
Transcription, in which RNA polymerases (RNAPs) produce RNA from DNA, is the first step of gene expression. As such, it is highly regulated either by trans-elements like protein factors and/or by cis-elements like specific sequences on the DNA. Lambdoid phage HK022 contains a cis-element, put, which suppresses pausing and termination during transcription of the early phage genes. The putRNA transcript solely performs the anti-pausing/termination activities by interacting directly with the E.coli RNAP elongation complex (EC) by an unknown structural mechanism. In this study, we reconstituted putRNA-associated ECs and determined the structures using cryo-electron microscopy. The determined structures of putRNA-associated EC, putRNA-absent EC, and σ70-bound EC suggest that the putRNA interaction with the EC counteracts swiveling, a conformational change previously identified to promote pausing and σ70 might modulate putRNA folding via σ70-dependent pausing during elongation.
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8
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Abstract
Shelterin is a multiprotein complex that plays central roles in telomere biology. Mutations in shelterin result in premature aging diseases and familial cancer predisposition. Mechanistic understanding of these so-called telomereopathies is hampered by our lack of knowledge regarding the structure and stoichiometry of shelterin. Here, we use multiple methods to probe the stoichiometry and conformational states of shelterin and reveal that it forms a fully dimeric complex with extensive conformational heterogeneity. Our results highlight the dynamic nature of this essential complex and explain why its high-resolution structure determination has yet to be achieved. Human shelterin is a six-subunit complex—composed of TRF1, TRF2, Rap1, TIN2, TPP1, and POT1—that binds telomeres, protects them from the DNA-damage response, and regulates the maintenance of telomeric DNA. Although high-resolution structures have been generated of the individual structured domains within shelterin, the architecture and stoichiometry of the full complex are currently unknown. Here, we report the purification of shelterin subcomplexes and reconstitution of the entire complex using full-length, recombinant subunits. By combining negative-stain electron microscopy (EM), cross-linking mass spectrometry (XLMS), AlphaFold modeling, mass photometry, and native mass spectrometry (MS), we obtain stoichiometries as well as domain-scale architectures of shelterin subcomplexes and determine that they feature extensive conformational heterogeneity. For POT1/TPP1 and POT1/TPP1/TIN2, we observe high variability in the positioning of the POT1 DNA-binding domain, the TPP1 oligonucleotide/oligosaccharide–binding (OB) fold, and the TIN2 TRFH domain with respect to the C-terminal domains of POT1. Truncation of unstructured linker regions in TIN2, TPP1, and POT1 did not reduce the conformational variability of the heterotrimer. Shelterin and TRF1-containing subcomplexes form fully dimeric stoichiometries, even in the absence of DNA substrates. Shelterin and its subcomplexes showed extensive conformational variability, regardless of the presence of DNA substrates. We conclude that shelterin adopts a multitude of conformations and argue that its unusual architectural variability is beneficial for its many functions at telomeres.
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9
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Rogawski R, Sharon M. Characterizing Endogenous Protein Complexes with Biological Mass Spectrometry. Chem Rev 2022; 122:7386-7414. [PMID: 34406752 PMCID: PMC9052418 DOI: 10.1021/acs.chemrev.1c00217] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Indexed: 01/11/2023]
Abstract
Biological mass spectrometry (MS) encompasses a range of methods for characterizing proteins and other biomolecules. MS is uniquely powerful for the structural analysis of endogenous protein complexes, which are often heterogeneous, poorly abundant, and refractive to characterization by other methods. Here, we focus on how biological MS can contribute to the study of endogenous protein complexes, which we define as complexes expressed in the physiological host and purified intact, as opposed to reconstituted complexes assembled from heterologously expressed components. Biological MS can yield information on complex stoichiometry, heterogeneity, topology, stability, activity, modes of regulation, and even structural dynamics. We begin with a review of methods for isolating endogenous complexes. We then describe the various biological MS approaches, focusing on the type of information that each method yields. We end with future directions and challenges for these MS-based methods.
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Affiliation(s)
- Rivkah Rogawski
- Department of Biomolecular
Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Michal Sharon
- Department of Biomolecular
Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
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10
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Giska F, Mariappan M, Bhattacharyya M, Gupta K. Deciphering the molecular organization of GET pathway chaperones through native mass spectrometry. Biophys J 2022; 121:1289-1298. [PMID: 35189106 PMCID: PMC9034188 DOI: 10.1016/j.bpj.2022.02.026] [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: 09/29/2021] [Revised: 10/25/2021] [Accepted: 02/15/2022] [Indexed: 11/02/2022] Open
Abstract
Get3/4/5 chaperone complex is responsible for targeting C-terminal tail-anchored membrane proteins to the endoplasmic reticulum. Despite the availability of several crystal structures of independent proteins and partial structures of subcomplexes, different models of oligomeric states and structural organization have been proposed for the protein complexes involved. Here, using native mass spectrometry (Native-MS), coupled with intact dissociation, we show that Get4/5 exclusively forms a tetramer using both Get5/5 and a novel Get4/4 dimerization interface. Addition of Get3 to this leads to a hexameric (Get3)2-(Get4)2-(Get5)2 complex with closed-ring cyclic architecture. We further validate our claims through molecular modeling and mutational abrogation of the proposed interfaces. Native-MS has become a principal tool to determine the state of oligomeric organization of proteins. The work demonstrates that for multiprotein complexes, native-MS, coupled with molecular modeling and mutational perturbation, can provide an alternative route to render a detailed view of both the oligomeric states as well as the molecular interfaces involved. This is especially useful for large multiprotein complexes with large unstructured domains that make it recalcitrant to conventional structure determination approaches.
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Affiliation(s)
- Fabian Giska
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut; Nanobiology Institute, Yale University, West Haven, Connecticut
| | - Malaiyalam Mariappan
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut; Nanobiology Institute, Yale University, West Haven, Connecticut
| | | | - Kallol Gupta
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut; Nanobiology Institute, Yale University, West Haven, Connecticut.
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11
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Mickolajczyk KJ, Olinares PDB, Chait BT, Liu S, Kapoor TM. The MIDAS domain of AAA mechanoenzyme Mdn1 forms catch bonds with two different substrates. eLife 2022; 11:73534. [PMID: 35147499 PMCID: PMC8837202 DOI: 10.7554/elife.73534] [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: 09/01/2021] [Accepted: 01/19/2022] [Indexed: 12/21/2022] Open
Abstract
Catch bonds are a form of mechanoregulation wherein protein-ligand interactions are strengthened by the application of dissociative tension. Currently, the best-characterized examples of catch bonds are between single protein-ligand pairs. The essential AAA (ATPase associated with diverse cellular activities) mechanoenzyme Mdn1 drives at least two separate steps in ribosome biogenesis, using its MIDAS domain to extract the ubiquitin-like (UBL) domain-containing proteins Rsa4 and Ytm1 from ribosomal precursors. However, it must subsequently release these assembly factors to reinitiate the enzymatic cycle. The mechanism underlying the switching of the MIDAS-UBL interaction between strongly and weakly bound states is unknown. Here, we use optical tweezers to investigate the force dependence of MIDAS-UBL binding. Parallel experiments with Rsa4 and Ytm1 show that forces up to ~4 pN, matching the magnitude of force produced by AAA proteins similar to Mdn1, enhance the MIDAS domain binding lifetime up to 10-fold, and higher forces accelerate dissociation. Together, our studies indicate that Mdn1's MIDAS domain can form catch bonds with more than one UBL substrate, and provide insights into how mechanoregulation may contribute to the Mdn1 enzymatic cycle during ribosome biogenesis.
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Affiliation(s)
- Keith J Mickolajczyk
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, United States
| | - Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, United States
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, United States
| | - Shixin Liu
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, United States
| | - Tarun M Kapoor
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, United States
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12
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Nudelman I, Fernandez-Martinez J, Rout MP. Affinity Isolation of Endogenous Saccharomyces Cerevisiae Nuclear Pore Complexes. Methods Mol Biol 2022; 2502:3-34. [PMID: 35412228 PMCID: PMC9200140 DOI: 10.1007/978-1-0716-2337-4_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Studying protein complexes in vitro requires the production of a relatively pure sample that maintains the full complement, native organization, and function of that complex. This can be particularly challenging to achieve for large, multi-component, membrane embedded complexes using the traditional recombinant expression and reconstitution methodologies. However, using affinity capture from native cells, suitable whole endogenous protein complexes can be isolated. Here we present a protocol for the affinity isolation of baker's yeast (S. cerevisiae) nuclear pore complexes, which are ~50 MDa assemblies made up of 552 distinct proteins and embedded in a double-membraned nuclear envelope. Producing this sample allowed us for the first time to perform analyses to characterize the mass, stoichiometry, morphology, and connectivity of this complex and to obtain its integrative structure with ~9 Å precision. We believe this methodology can be applied to other challenging protein complexes to produce similar results.
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Affiliation(s)
- Ilona Nudelman
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY, USA
- Fisher Drug Discovery Resource Center (DDRC), The Rockefeller University, New York, NY, USA
| | - Javier Fernandez-Martinez
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY, USA
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, Leioa, Bizkaia, Spain
| | - Michael P Rout
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY, USA.
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13
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Niu Y, Tao X, Vaisey G, Olinares PDB, Alwaseem H, Chait BT, MacKinnon R. Analysis of the mechanosensor channel functionality of TACAN. eLife 2021; 10:71188. [PMID: 34374644 PMCID: PMC8376246 DOI: 10.7554/elife.71188] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/06/2021] [Indexed: 02/06/2023] Open
Abstract
Mechanosensitive ion channels mediate transmembrane ion currents activated by mechanical forces. A mechanosensitive ion channel called TACAN was recently reported. We began to study TACAN with the intent to understand how it senses mechanical forces and functions as an ion channel. Using cellular patch-recording methods, we failed to identify mechanosensitive ion channel activity. Using membrane reconstitution methods, we found that TACAN, at high protein concentrations, produces heterogeneous conduction levels that are not mechanosensitive and are most consistent with disruptions of the lipid bilayer. We determined the structure of TACAN using single-particle cryo-electron microscopy and observed that it is a symmetrical dimeric transmembrane protein. Each protomer contains an intracellular-facing cleft with a coenzyme A cofactor, confirmed by mass spectrometry. The TACAN protomer is related in three-dimensional structure to a fatty acid elongase, ELOVL7. Whilst its physiological function remains unclear, we anticipate that TACAN is not a mechanosensitive ion channel.
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Affiliation(s)
- Yiming Niu
- Laboratory of Molecular Neurobiology and Biophysics, Rockefeller University, New York, United States
| | - Xiao Tao
- Laboratory of Molecular Neurobiology and Biophysics, Rockefeller University, New York, United States.,Howard Hughes Medical Institute, New York, United States
| | - George Vaisey
- Laboratory of Molecular Neurobiology and Biophysics, Rockefeller University, New York, United States.,Howard Hughes Medical Institute, New York, United States
| | - Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, Rockefeller University, New York, United States
| | - Hanan Alwaseem
- Proteomics Resource Center, Rockefeller University, New York, United States
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, Rockefeller University, New York, United States
| | - Roderick MacKinnon
- Laboratory of Molecular Neurobiology and Biophysics, Rockefeller University, New York, United States.,Howard Hughes Medical Institute, New York, United States
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14
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Olinares PDB, Kang JY, Llewellyn E, Chiu C, Chen J, Malone B, Saecker RM, Campbell EA, Darst SA, Chait BT. Native Mass Spectrometry-Based Screening for Optimal Sample Preparation in Single-Particle Cryo-EM. Structure 2021; 29:186-195.e6. [PMID: 33217329 PMCID: PMC7867593 DOI: 10.1016/j.str.2020.11.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/26/2020] [Accepted: 11/02/2020] [Indexed: 01/19/2023]
Abstract
Recent advances in single-particle cryogenic electron microscopy (cryo-EM) have enabled the structural determination of numerous protein assemblies at high resolution, yielding unprecedented insights into their function. However, despite its extraordinary capabilities, cryo-EM remains time-consuming and resource-intensive. It is therefore beneficial to have a means for rapidly assessing and optimizing the quality of samples prior to lengthy cryo-EM analyses. To do this, we have developed a native mass spectrometry (nMS) platform that provides rapid feedback on sample quality and highly streamlined biochemical screening. Because nMS enables accurate mass analysis of protein complexes, it is well suited to routine evaluation of the composition, integrity, and homogeneity of samples prior to their plunge-freezing on EM grids. We demonstrate the utility of our nMS-based platform for facilitating cryo-EM studies using structural characterizations of exemplar bacterial transcription complexes as well as the replication-transcription assembly from the SARS-CoV-2 virus that is responsible for the COVID-19 pandemic.
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Affiliation(s)
- Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY 10065, USA.
| | - Jin Young Kang
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Eliza Llewellyn
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Courtney Chiu
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - James Chen
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Brandon Malone
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Ruth M Saecker
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Seth A Darst
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY 10065, USA.
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15
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Kang JY, Llewellyn E, Chen J, Olinares PDB, Brewer J, Chait BT, Campbell EA, Darst SA. Structural basis for transcription complex disruption by the Mfd translocase. eLife 2021; 10:62117. [PMID: 33480355 PMCID: PMC7864632 DOI: 10.7554/elife.62117] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 01/21/2021] [Indexed: 12/30/2022] Open
Abstract
Transcription-coupled repair (TCR) is a sub-pathway of nucleotide excision repair (NER) that preferentially removes lesions from the template-strand (t-strand) that stall RNA polymerase (RNAP) elongation complexes (ECs). Mfd mediates TCR in bacteria by removing the stalled RNAP concealing the lesion and recruiting Uvr(A)BC. We used cryo-electron microscopy to visualize Mfd engaging with a stalled EC and attempting to dislodge the RNAP. We visualized seven distinct Mfd-EC complexes in both ATP and ADP-bound states. The structures explain how Mfd is remodeled from its repressed conformation, how the UvrA-interacting surface of Mfd is hidden during most of the remodeling process to prevent premature engagement with the NER pathway, how Mfd alters the RNAP conformation to facilitate disassembly, and how Mfd forms a processive translocation complex after dislodging the RNAP. Our results reveal an elaborate mechanism for how Mfd kinetically discriminates paused from stalled ECs and disassembles stalled ECs to initiate TCR.
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Affiliation(s)
- Jin Young Kang
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, United States
| | - Eliza Llewellyn
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, United States
| | - James Chen
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, United States
| | - Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, United States
| | - Joshua Brewer
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, United States
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, United States
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, United States
| | - Seth A Darst
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, United States
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16
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Schureck MA, Darling JE, Merk A, Shao J, Daggupati G, Srinivasan P, Olinares PDB, Rout MP, Chait BT, Wollenberg K, Subramaniam S, Desai SA. Malaria parasites use a soluble RhopH complex for erythrocyte invasion and an integral form for nutrient uptake. eLife 2021; 10:e65282. [PMID: 33393463 PMCID: PMC7840181 DOI: 10.7554/elife.65282] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 01/04/2021] [Indexed: 12/12/2022] Open
Abstract
Malaria parasites use the RhopH complex for erythrocyte invasion and channel-mediated nutrient uptake. As the member proteins are unique to Plasmodium spp., how they interact and traffic through subcellular sites to serve these essential functions is unknown. We show that RhopH is synthesized as a soluble complex of CLAG3, RhopH2, and RhopH3 with 1:1:1 stoichiometry. After transfer to a new host cell, the complex crosses a vacuolar membrane surrounding the intracellular parasite and becomes integral to the erythrocyte membrane through a PTEX translocon-dependent process. We present a 2.9 Å single-particle cryo-electron microscopy structure of the trafficking complex, revealing that CLAG3 interacts with the other subunits over large surface areas. This soluble complex is tightly assembled with extensive disulfide bonding and predicted transmembrane helices shielded. We propose a large protein complex stabilized for trafficking but poised for host membrane insertion through large-scale rearrangements, paralleling smaller two-state pore-forming proteins in other organisms.
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Affiliation(s)
- Marc A Schureck
- Laboratory of Malaria and Vector Research, NIAID, National Institutes of HealthRockvilleUnited States
| | - Joseph E Darling
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of HealthBethesdaUnited States
| | - Alan Merk
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of HealthBethesdaUnited States
| | - Jinfeng Shao
- Laboratory of Malaria and Vector Research, NIAID, National Institutes of HealthRockvilleUnited States
| | - Geervani Daggupati
- Department of Molecular Microbiology and Immunology, and Johns Hopkins Malaria Institute, Johns Hopkins Bloomberg School of Public HealthBaltimoreUnited States
| | - Prakash Srinivasan
- Department of Molecular Microbiology and Immunology, and Johns Hopkins Malaria Institute, Johns Hopkins Bloomberg School of Public HealthBaltimoreUnited States
| | - Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller UniversityNew YorkUnited States
| | - Michael P Rout
- Laboratory of Cellular and Structural Biology, The Rockefeller UniversityNew YorkUnited States
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller UniversityNew YorkUnited States
| | - Kurt Wollenberg
- Office of Cyber Infrastructure & Computational Biology, National Institute of Allergy and Infectious Diseases, National Institutes of HealthBethesdaUnited States
| | - Sriram Subramaniam
- Department of Biochemistry and Molecular Biology, University of British ColumbiaVancouverCanada
| | - Sanjay A Desai
- Laboratory of Malaria and Vector Research, NIAID, National Institutes of HealthRockvilleUnited States
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17
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Chen J, Malone B, Llewellyn E, Grasso M, Shelton PM, Olinares PDB, Maruthi K, Eng ET, Vatandaslar H, Chait BT, Kapoor TM, Darst SA, Campbell EA. Structural Basis for Helicase-Polymerase Coupling in the SARS-CoV-2 Replication-Transcription Complex. Cell 2020; 182:1560-1573.e13. [PMID: 32783916 PMCID: PMC7386476 DOI: 10.1016/j.cell.2020.07.033] [Citation(s) in RCA: 309] [Impact Index Per Article: 77.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/10/2020] [Accepted: 07/22/2020] [Indexed: 01/21/2023]
Abstract
SARS-CoV-2 is the causative agent of the 2019-2020 pandemic. The SARS-CoV-2 genome is replicated and transcribed by the RNA-dependent RNA polymerase holoenzyme (subunits nsp7/nsp82/nsp12) along with a cast of accessory factors. One of these factors is the nsp13 helicase. Both the holo-RdRp and nsp13 are essential for viral replication and are targets for treating the disease COVID-19. Here we present cryoelectron microscopic structures of the SARS-CoV-2 holo-RdRp with an RNA template product in complex with two molecules of the nsp13 helicase. The Nidovirales order-specific N-terminal domains of each nsp13 interact with the N-terminal extension of each copy of nsp8. One nsp13 also contacts the nsp12 thumb. The structure places the nucleic acid-binding ATPase domains of the helicase directly in front of the replicating-transcribing holo-RdRp, constraining models for nsp13 function. We also observe ADP-Mg2+ bound in the nsp12 N-terminal nidovirus RdRp-associated nucleotidyltransferase domain, detailing a new pocket for anti-viral therapy development.
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Affiliation(s)
- James Chen
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Brandon Malone
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Eliza Llewellyn
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Michael Grasso
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY 10065, USA
| | - Patrick M.M. Shelton
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY 10065, USA
| | - Paul Dominic B. Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY 10065, USA
| | - Kashyap Maruthi
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Edward T. Eng
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Hasan Vatandaslar
- Institute of Molecular Health Sciences, ETH Zürich, 8093 Zürich, Switzerland
| | - Brian T. Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY 10065, USA
| | - Tarun M. Kapoor
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY 10065, USA
| | - Seth A. Darst
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA,Corresponding author
| | - Elizabeth A. Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA,Corresponding author
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18
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Long-range intramolecular allostery and regulation in the dynein-like AAA protein Mdn1. Proc Natl Acad Sci U S A 2020; 117:18459-18469. [PMID: 32694211 DOI: 10.1073/pnas.2002792117] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mdn1 is an essential mechanoenzyme that uses the energy from ATP hydrolysis to physically reshape and remodel, and thus mature, the 60S subunit of the ribosome. This massive (>500 kDa) protein has an N-terminal AAA (ATPase associated with diverse cellular activities) ring, which, like dynein, has six ATPase sites. The AAA ring is followed by large (>2,000 aa) linking domains that include an ∼500-aa disordered (D/E-rich) region, and a C-terminal substrate-binding MIDAS domain. Recent models suggest that intramolecular docking of the MIDAS domain onto the AAA ring is required for Mdn1 to transmit force to its ribosomal substrates, but it is not currently understood what role the linking domains play, or why tethering the MIDAS domain to the AAA ring is required for protein function. Here, we use chemical probes, single-particle electron microscopy, and native mass spectrometry to study the AAA and MIDAS domains separately or in combination. We find that Mdn1 lacking the D/E-rich and MIDAS domains retains ATP and chemical probe binding activities. Free MIDAS domain can bind to the AAA ring of this construct in a stereo-specific bimolecular interaction, and, interestingly, this binding reduces ATPase activity. Whereas intramolecular MIDAS docking appears to require a treatment with a chemical inhibitor or preribosome binding, bimolecular MIDAS docking does not. Hence, tethering the MIDAS domain to the AAA ring serves to prevent, rather than promote, MIDAS docking in the absence of inducing signals.
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19
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Chen J, Malone B, Llewellyn E, Grasso M, Shelton PMM, Olinares PDB, Maruthi K, Eng E, Vatandaslar H, Chait BT, Kapoor T, Darst SA, Campbell EA. Structural basis for helicase-polymerase coupling in the SARS-CoV-2 replication-transcription complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020. [PMID: 32676607 PMCID: PMC7359531 DOI: 10.1101/2020.07.08.194084] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
SARS-CoV-2 is the causative agent of the 2019-2020 pandemic. The SARS-CoV-2 genome is replicated-transcribed by the RNA-dependent RNA polymerase holoenzyme (subunits nsp7/nsp82/nsp12) along with a cast of accessory factors. One of these factors is the nsp13 helicase. Both the holo-RdRp and nsp13 are essential for viral replication and are targets for treating the disease COVID-19. Here we present cryo-electron microscopic structures of the SARS-CoV-2 holo-RdRp with an RNA template-product in complex with two molecules of the nsp13 helicase. The Nidovirus-order-specific N-terminal domains of each nsp13 interact with the N-terminal extension of each copy of nsp8. One nsp13 also contacts the nsp12-thumb. The structure places the nucleic acid-binding ATPase domains of the helicase directly in front of the replicating-transcribing holo-RdRp, constraining models for nsp13 function. We also observe ADP-Mg2+ bound in the nsp12 N-terminal nidovirus RdRp-associated nucleotidyltransferase domain, detailing a new pocket for anti-viral therapeutic development.
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Affiliation(s)
- James Chen
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, 10065 USA
| | - Brandon Malone
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, 10065 USA
| | - Eliza Llewellyn
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, 10065 USA
| | - Michael Grasso
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY, 10065 USA
| | - Patrick M M Shelton
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY, 10065 USA
| | - Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, 10065 USA
| | - Kashyap Maruthi
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, 10027 USA
| | - Ed Eng
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, 10027 USA
| | - Hasan Vatandaslar
- Institute of Molecular Health Sciences, ETH Zurich, 8093 Zürich, Switzerland
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, 10065 USA
| | - Tarun Kapoor
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY, 10065 USA
| | - Seth A Darst
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, 10065 USA
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, 10065 USA
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