1
|
Morgenstern TJ, Darko-Boateng A, Afriyie E, Shanmugam SK, Zhou X, Choudhury P, Desai M, Kass RS, Clarke OB, Colecraft HM. Ion channel inhibition by targeted recruitment of NEDD4-2 with divalent nanobodies. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.28.596281. [PMID: 38854018 PMCID: PMC11160594 DOI: 10.1101/2024.05.28.596281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Targeted recruitment of E3 ubiquitin ligases to degrade traditionally undruggable proteins is a disruptive paradigm for developing new therapeutics. Two salient limitations are that <2% of the ~600 E3 ligases in the human genome have been exploited to produce proteolysis targeting chimeras (PROTACs), and the efficacy of the approach has not been demonstrated for a vital class of complex multi-subunit membrane proteins- ion channels. NEDD4-1 and NEDD4-2 are physiological regulators of myriad ion channels, and belong to the 28-member HECT (homologous to E6AP C-terminus) family of E3 ligases with widespread roles in cell/developmental biology and diverse diseases including various cancers, immunological and neurological disorders, and chronic pain. The potential efficacy of HECT E3 ligases for targeted protein degradation is unexplored, constrained by a lack of appropriate binders, and uncertain due to their complex regulation by layered intra-molecular and posttranslational mechanisms. Here, we identified a nanobody that binds with high affinity and specificity to a unique site on the N-lobe of the NEDD4-2 HECT domain at a location physically separate from sites critical for catalysis- the E2 binding site, the catalytic cysteine, and the ubiquitin exosite- as revealed by a 3.1 Å cryo-electron microscopy reconstruction. Recruiting endogenous NEDD4-2 to diverse ion channel proteins (KCNQ1, ENaC, and CaV2.2) using a divalent (DiVa) nanobody format strongly reduced their functional expression with minimal off-target effects as assessed by global proteomics, compared to simple NEDD4-2 overexpression. The results establish utility of a HECT E3 ligase for targeted protein downregulation, validate a class of complex multi-subunit membrane proteins as susceptible to this modality, and introduce endogenous E3 ligase recruitment with DiVa nanobodies as a general method to generate novel genetically-encoded ion channel inhibitors.
Collapse
Affiliation(s)
- Travis J. Morgenstern
- Department of Molecular Pharmacology and Therapeutics, Columbia University Irving Medical Center, New York, NY
| | - Arden Darko-Boateng
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY
| | - Emmanuel Afriyie
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY
| | - Sri Karthika Shanmugam
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY
| | - Xinle Zhou
- Department of Molecular Pharmacology and Therapeutics, Columbia University Irving Medical Center, New York, NY
| | - Papiya Choudhury
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY
| | | | - Robert S. Kass
- Department of Molecular Pharmacology and Therapeutics, Columbia University Irving Medical Center, New York, NY
| | - Oliver B. Clarke
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY
- Department of Anesthesiology, Columbia University Irving Medical Center, New York, NY
| | - Henry M. Colecraft
- Department of Molecular Pharmacology and Therapeutics, Columbia University Irving Medical Center, New York, NY
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY
| |
Collapse
|
2
|
Nygaard R, Graham CLB, Belcher Dufrisne M, Colburn JD, Pepe J, Hydorn MA, Corradi S, Brown CM, Ashraf KU, Vickery ON, Briggs NS, Deering JJ, Kloss B, Botta B, Clarke OB, Columbus L, Dworkin J, Stansfeld PJ, Roper DI, Mancia F. Structural basis of peptidoglycan synthesis by E. coli RodA-PBP2 complex. Nat Commun 2023; 14:5151. [PMID: 37620344 PMCID: PMC10449877 DOI: 10.1038/s41467-023-40483-8] [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: 11/11/2022] [Accepted: 07/31/2023] [Indexed: 08/26/2023] Open
Abstract
Peptidoglycan (PG) is an essential structural component of the bacterial cell wall that is synthetized during cell division and elongation. PG forms an extracellular polymer crucial for cellular viability, the synthesis of which is the target of many antibiotics. PG assembly requires a glycosyltransferase (GT) to generate a glycan polymer using a Lipid II substrate, which is then crosslinked to the existing PG via a transpeptidase (TP) reaction. A Shape, Elongation, Division and Sporulation (SEDS) GT enzyme and a Class B Penicillin Binding Protein (PBP) form the core of the multi-protein complex required for PG assembly. Here we used single particle cryo-electron microscopy to determine the structure of a cell elongation-specific E. coli RodA-PBP2 complex. We combine this information with biochemical, genetic, spectroscopic, and computational analyses to identify the Lipid II binding sites and propose a mechanism for Lipid II polymerization. Our data suggest a hypothesis for the movement of the glycan strand from the Lipid II polymerization site of RodA towards the TP site of PBP2, functionally linking these two central enzymatic activities required for cell wall peptidoglycan biosynthesis.
Collapse
Affiliation(s)
- Rie Nygaard
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Chris L B Graham
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Meagan Belcher Dufrisne
- Department of Chemistry and Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, 22904, USA
| | - Jonathan D Colburn
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
| | - Joseph Pepe
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Molly A Hydorn
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Silvia Corradi
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY, 10032, USA
- Faculty of Pharmacy and Medicine, Sapienza University of Rome, Rome, Italy
| | - Chelsea M Brown
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
| | - Khuram U Ashraf
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Owen N Vickery
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
| | - Nicholas S Briggs
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - John J Deering
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Brian Kloss
- New York Consortium on Membrane Protein Structure, New York Structural Biology Center, 89 Convent Avenue, New York, NY, 10027, USA
| | - Bruno Botta
- Faculty of Pharmacy and Medicine, Sapienza University of Rome, Rome, Italy
| | - Oliver B Clarke
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY, 10032, USA
- Department of Anesthesiology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Linda Columbus
- Department of Chemistry and Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, 22904, USA.
| | - Jonathan Dworkin
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA.
| | - Phillip J Stansfeld
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK.
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK.
| | - David I Roper
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK.
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY, 10032, USA.
| |
Collapse
|
3
|
Panigrahi R, Glover JNM, Nallusamy S. A look into DGAT1 through the EM lenses. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184069. [PMID: 36216097 DOI: 10.1016/j.bbamem.2022.184069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 10/03/2022] [Indexed: 11/05/2022]
Abstract
With the advent of modern detectors and robust structure solution pipeline, cryogenic electron microscopy has recently proved to be game changer in structural biology. Membrane proteins are challenging targets for structural biologists. This minireview focuses a membrane embedded triglyceride synthesizing machine, DGAT1. Decades of research had built the foundational knowledge on this enzyme's activity. However, recently solved cryo-EM structures of this enzyme, in apo and bound form, has provided critical mechanistic insights. The flipping of the catalytic histidine is critical of enzyme catalysis. The structures explain why the enzyme has preference to long fatty acyl chains over the short forms.
Collapse
Affiliation(s)
- Rashmi Panigrahi
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
| | - J N Mark Glover
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Saranya Nallusamy
- Department of Plant Molecular Biology and Bioinformatics, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore 641003, India.
| |
Collapse
|
4
|
Ashraf KU, Nygaard R, Vickery ON, Erramilli SK, Herrera CM, McConville TH, Petrou VI, Giacometti SI, Dufrisne MB, Nosol K, Zinkle AP, Graham CLB, Loukeris M, Kloss B, Skorupinska-Tudek K, Swiezewska E, Roper DI, Clarke OB, Uhlemann AC, Kossiakoff AA, Trent MS, Stansfeld PJ, Mancia F. Structural basis of lipopolysaccharide maturation by the O-antigen ligase. Nature 2022; 604:371-376. [PMID: 35388216 PMCID: PMC9884178 DOI: 10.1038/s41586-022-04555-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 02/16/2022] [Indexed: 01/31/2023]
Abstract
The outer membrane of Gram-negative bacteria has an external leaflet that is largely composed of lipopolysaccharide, which provides a selective permeation barrier, particularly against antimicrobials1. The final and crucial step in the biosynthesis of lipopolysaccharide is the addition of a species-dependent O-antigen to the lipid A core oligosaccharide, which is catalysed by the O-antigen ligase WaaL2. Here we present structures of WaaL from Cupriavidus metallidurans, both in the apo state and in complex with its lipid carrier undecaprenyl pyrophosphate, determined by single-particle cryo-electron microscopy. The structures reveal that WaaL comprises 12 transmembrane helices and a predominantly α-helical periplasmic region, which we show contains many of the conserved residues that are required for catalysis. We observe a conserved fold within the GT-C family of glycosyltransferases and hypothesize that they have a common mechanism for shuttling the undecaprenyl-based carrier to and from the active site. The structures, combined with genetic, biochemical, bioinformatics and molecular dynamics simulation experiments, offer molecular details on how the ligands come in apposition, and allows us to propose a mechanistic model for catalysis. Together, our work provides a structural basis for lipopolysaccharide maturation in a member of the GT-C superfamily of glycosyltransferases.
Collapse
Affiliation(s)
- Khuram U Ashraf
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY, USA
| | - Rie Nygaard
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY, USA
| | - Owen N Vickery
- School of Life Sciences, University of Warwick, Coventry, UK
- Department of Chemistry, University of Warwick, Coventry, UK
| | - Satchal K Erramilli
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - Carmen M Herrera
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - Thomas H McConville
- Department of Medicine, Division of Infectious Diseases, Columbia University Medical Center, New York, NY, USA
| | - Vasileios I Petrou
- Department of Microbiology, Biochemistry, and Molecular Genetics, New Jersey Medical School, Rutgers Biomedical Health Sciences, Newark, NJ, USA
- Center for Immunity and Inflammation, New Jersey Medical School, Rutgers Biomedical Health Sciences, Newark, NJ, USA
| | - Sabrina I Giacometti
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY, USA
| | - Meagan Belcher Dufrisne
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY, USA
| | - Kamil Nosol
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - Allen P Zinkle
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY, USA
| | | | - Michael Loukeris
- New York Consortium on Membrane Protein Structure, New York Structural Biology Center, New York, NY, USA
| | - Brian Kloss
- New York Consortium on Membrane Protein Structure, New York Structural Biology Center, New York, NY, USA
| | | | - Ewa Swiezewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - David I Roper
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY, USA
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Oliver B Clarke
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY, USA
- Department of Anesthesiology, Columbia University Irving Medical Center, New York, NY, USA
| | - Anne-Catrin Uhlemann
- Department of Medicine, Division of Infectious Diseases, Columbia University Medical Center, New York, NY, USA
| | - Anthony A Kossiakoff
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - M Stephen Trent
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.
| | - Phillip J Stansfeld
- School of Life Sciences, University of Warwick, Coventry, UK.
- Department of Chemistry, University of Warwick, Coventry, UK.
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY, USA.
| |
Collapse
|
5
|
Nygaard R, Kim J, Mancia F. Cryo-electron microscopy analysis of small membrane proteins. Curr Opin Struct Biol 2020; 64:26-33. [PMID: 32603877 PMCID: PMC7665978 DOI: 10.1016/j.sbi.2020.05.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/05/2020] [Accepted: 05/19/2020] [Indexed: 12/31/2022]
Abstract
Recent advances in single-particle cryogenic-electron microscopy have facilitated an exponential growth in the number of membrane protein structures determined to close to atomic resolution. Nevertheless, despite improvements in microscope hardware, cryo-EM software and sample preparation techniques, challenges remain for structural analysis of small-sized membrane proteins (i.e.<150 kilodalton). Here we discuss recent examples of structures of macromolecules from this category determined by cryo-EM. We analyze the underlying difficulties, the enabling technologies such as the use of antibody fragments to gain size and provide fiducials for particle alignment, and the unresolved issues like dislocation of complexes at the air-water interface. Finally, we briefly highlight the biological relevance of some of these success stories, and our predictions for the future.
Collapse
Affiliation(s)
- Rie Nygaard
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Jonathan Kim
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY 10032, USA.
| |
Collapse
|
6
|
Lee JY, Dang K, Liu A, Alba BM. Automated buffer preparation using quaternary valve in fast performance liquid chromatography for protein purification from a cell membrane. J Chromatogr B Analyt Technol Biomed Life Sci 2020; 1136:121849. [PMID: 31841981 DOI: 10.1016/j.jchromb.2019.121849] [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: 04/21/2019] [Revised: 10/06/2019] [Indexed: 10/25/2022]
Abstract
There is a great need for high-throughput protein purification to produce protein molecules for research and therapeutics. Although there have been significant advancements made in automated multi-step chromatography and preparative in-process design-of-experiment (DOE) capabilities in commercial fast performance liquid chromatography (FPLC) instruments, almost all commercial FPLCs rely on a binary buffer mixing system, which hinders automated buffer preparation. Nevertheless, current-generation FPLCs are equipped with a quaternary mixer designed for limited in-line buffer preparation and preparative pH scouting DOE experiments. We decided to leverage the quaternary mixing capability by extending and re-programming AkTA Avant's quaternary valve into an automated in-process buffer preparation system to simplify automated purification requiring complex washing steps. We accomplished this by using two extra inlet valves, a sample valve, and versatile valve to split inputs of the quaternary valve into software-selectable stock solutions of pH buffers, salts, eluents, and additives. We also devised a new flow scheme to perform automated two-step chromatography using only one versatile valve. This was accomplished by using only stock parts and software to facilitate reproduction. To demonstrate the versatility and capability of the system, we purified a transmembrane protein that requires a detergent to stay soluble and needs an in-column, high-salt washing step to achieve high purity.
Collapse
Affiliation(s)
- Jonas Y Lee
- Department of Therapeutic Discovery, Amgen Research, 1120 Veterans Blvd, South San Francisco, CA 94080, United States; Current address: Janssen Research and Development, 3210 Merryfield Row, San Diego, CA 92121, United States
| | - Khue Dang
- Department of Therapeutic Discovery, Amgen Research, 1120 Veterans Blvd, South San Francisco, CA 94080, United States
| | - Alan Liu
- Department of Therapeutic Discovery, Amgen Research, 1120 Veterans Blvd, South San Francisco, CA 94080, United States
| | - Benjamin M Alba
- Department of Therapeutic Discovery, Amgen Research, 1120 Veterans Blvd, South San Francisco, CA 94080, United States.
| |
Collapse
|
7
|
Assur Sanghai Z, Liu Q, Clarke OB, Belcher-Dufrisne M, Wiriyasermkul P, Giese MH, Leal-Pinto E, Kloss B, Tabuso S, Love J, Punta M, Banerjee S, Rajashankar KR, Rost B, Logothetis D, Quick M, Hendrickson WA, Mancia F. Structure-based analysis of CysZ-mediated cellular uptake of sulfate. eLife 2018; 7:27829. [PMID: 29792261 PMCID: PMC5967866 DOI: 10.7554/elife.27829] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 04/11/2018] [Indexed: 01/25/2023] Open
Abstract
Sulfur, most abundantly found in the environment as sulfate (SO42-), is an essential element in metabolites required by all living cells, including amino acids, co-factors and vitamins. However, current understanding of the cellular delivery of SO42- at the molecular level is limited. CysZ has been described as a SO42- permease, but its sequence family is without known structural precedent. Based on crystallographic structure information, SO42- binding and flux experiments, we provide insight into the molecular mechanism of CysZ-mediated translocation of SO42- across membranes. CysZ structures from three different bacterial species display a hitherto unknown fold and have subunits organized with inverted transmembrane topology. CysZ from Pseudomonas denitrificans assembles as a trimer of antiparallel dimers and the CysZ structures from two other species recapitulate dimers from this assembly. Mutational studies highlight the functional relevance of conserved CysZ residues.
Collapse
Affiliation(s)
- Zahra Assur Sanghai
- Department of Physiology and Cellular Biophysics, Columbia University, New York, United States.,Department of Biochemistry and Molecular Biophysics, Columbia University, New York, United States
| | - Qun Liu
- Biology Department, Brookhaven National Laboratory, Upton, United States
| | - Oliver B Clarke
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, United States
| | - Meagan Belcher-Dufrisne
- Department of Physiology and Cellular Biophysics, Columbia University, New York, United States
| | - Pattama Wiriyasermkul
- Center for Molecular Recognition, Department of Psychiatry, Columbia University, New York, United States
| | - M Hunter Giese
- Department of Physiology and Cellular Biophysics, Columbia University, New York, United States.,Department of Biochemistry and Molecular Biophysics, Columbia University, New York, United States
| | - Edgar Leal-Pinto
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, United States.,Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, United States
| | - Brian Kloss
- New York Structural Biology Center, New York, United States
| | | | - James Love
- New York Structural Biology Center, New York, United States
| | - Marco Punta
- Centre for Evolution and Cancer, The Institute of Cancer Research, London, United Kingdom
| | - Surajit Banerjee
- Department of Chemistry and Chemical Biology, Cornell University, NE-CAT, Argonne, United States
| | | | - Burkhard Rost
- Department of Informatics, Technical University of Munich, Munich, Germany
| | - Diomedes Logothetis
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, United States.,Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, United States
| | - Matthias Quick
- Center for Molecular Recognition, Department of Psychiatry, Columbia University, New York, United States.,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, United States
| | - Wayne A Hendrickson
- Department of Physiology and Cellular Biophysics, Columbia University, New York, United States.,Department of Biochemistry and Molecular Biophysics, Columbia University, New York, United States.,New York Structural Biology Center, New York, United States
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University, New York, United States
| |
Collapse
|
8
|
Ahmad I, Nawaz N, Darwesh NM, ur Rahman S, Mustafa MZ, Khan SB, Patching SG. Overcoming challenges for amplified expression of recombinant proteins using Escherichia coli. Protein Expr Purif 2018; 144:12-18. [DOI: 10.1016/j.pep.2017.11.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 11/15/2017] [Accepted: 11/21/2017] [Indexed: 11/28/2022]
|
9
|
Magnani F, Serrano-Vega MJ, Shibata Y, Abdul-Hussein S, Lebon G, Miller-Gallacher J, Singhal A, Strege A, Thomas JA, Tate CG. A mutagenesis and screening strategy to generate optimally thermostabilized membrane proteins for structural studies. Nat Protoc 2016; 11:1554-71. [PMID: 27466713 PMCID: PMC5268090 DOI: 10.1038/nprot.2016.088] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The thermostability of an integral membrane protein (MP) in detergent solution is a key parameter that dictates the likelihood of obtaining well-diffracting crystals that are suitable for structure determination. However, many mammalian MPs are too unstable for crystallization. We developed a thermostabilization strategy based on systematic mutagenesis coupled to a radioligand-binding thermostability assay that can be applied to receptors, ion channels and transporters. It takes ∼6-12 months to thermostabilize a G-protein-coupled receptor (GPCR) containing 300 amino acid (aa) residues. The resulting thermostabilized MPs are more easily crystallized and result in high-quality structures. This methodology has facilitated structure-based drug design applied to GPCRs because it is possible to determine multiple structures of the thermostabilized receptors bound to low-affinity ligands. Protocols and advice are given on how to develop thermostability assays for MPs and how to combine mutations to make an optimally stable mutant suitable for structural studies. The steps in the procedure include the generation of ∼300 site-directed mutants by Ala/Leu scanning mutagenesis, the expression of each mutant in mammalian cells by transient transfection and the identification of thermostable mutants using a thermostability assay that is based on binding of an (125)I-labeled radioligand to the unpurified, detergent-solubilized MP. Individual thermostabilizing point mutations are then combined to make an optimally stable MP that is suitable for structural biology and other biophysical studies.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Ankita Singhal
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Annette Strege
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Jennifer A. Thomas
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Christopher G. Tate
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| |
Collapse
|
10
|
Ardiccioni C, Clarke OB, Tomasek D, Issa HA, von Alpen DC, Pond HL, Banerjee S, Rajashankar KR, Liu Q, Guan Z, Li C, Kloss B, Bruni R, Kloppmann E, Rost B, Manzini MC, Shapiro L, Mancia F. Structure of the polyisoprenyl-phosphate glycosyltransferase GtrB and insights into the mechanism of catalysis. Nat Commun 2016; 7:10175. [PMID: 26729507 PMCID: PMC4728340 DOI: 10.1038/ncomms10175] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 11/11/2015] [Indexed: 11/08/2022] Open
Abstract
The attachment of a sugar to a hydrophobic polyisoprenyl carrier is the first step for all extracellular glycosylation processes. The enzymes that perform these reactions, polyisoprenyl-glycosyltransferases (PI-GTs) include dolichol phosphate mannose synthase (DPMS), which generates the mannose donor for glycosylation in the endoplasmic reticulum. Here we report the 3.0 Å resolution crystal structure of GtrB, a glucose-specific PI-GT from Synechocystis, showing a tetramer in which each protomer contributes two helices to a membrane-spanning bundle. The active site is 15 Å from the membrane, raising the question of how water-soluble and membrane-embedded substrates are brought into apposition for catalysis. A conserved juxtamembrane domain harbours disease mutations, which compromised activity in GtrB in vitro and in human DPM1 tested in zebrafish. We hypothesize a role of this domain in shielding the polyisoprenyl-phosphate for transport to the active site. Our results reveal the basis of PI-GT function, and provide a potential molecular explanation for DPM1-related disease.
Collapse
Affiliation(s)
- Chiara Ardiccioni
- Department of Physiology and Cellular Biophysics, Columbia University, New York, New York 10032, USA
| | - Oliver B. Clarke
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032, USA
| | - David Tomasek
- Department of Physiology and Cellular Biophysics, Columbia University, New York, New York 10032, USA
| | - Habon A. Issa
- Department of Pharmacology and Physiology, George Washington University, Washington, District of Columbia 20037, USA
- Department of Integrative Systems Biology, George Washington University, Washington, District of Columbia 20037, USA
| | - Desiree C. von Alpen
- Department of Pharmacology and Physiology, George Washington University, Washington, District of Columbia 20037, USA
- Department of Integrative Systems Biology, George Washington University, Washington, District of Columbia 20037, USA
| | - Heather L. Pond
- Department of Pharmacology and Physiology, George Washington University, Washington, District of Columbia 20037, USA
- Department of Integrative Systems Biology, George Washington University, Washington, District of Columbia 20037, USA
| | - Surajit Banerjee
- NE-CAT and Department of Chemistry and Chemical Biology, Cornell University, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Kanagalaghatta R. Rajashankar
- NE-CAT and Department of Chemistry and Chemical Biology, Cornell University, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Qun Liu
- New York Structural Biology Center, X4 Beamlines, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Ziqiang Guan
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Chijun Li
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Brian Kloss
- New York Consortium on Membrane Protein Structure, New York Structural Biology Center, New York, New York 10027, USA
| | - Renato Bruni
- New York Consortium on Membrane Protein Structure, New York Structural Biology Center, New York, New York 10027, USA
| | - Edda Kloppmann
- Department of Informatics, Bioinformatics and Computational Biology, Garching 85748, Germany
- Institute for Advanced Study (TUM-IAS), TUM (Technische Universität München), Garching 85748, Germany
| | - Burkhard Rost
- Department of Informatics, Bioinformatics and Computational Biology, Garching 85748, Germany
- Institute for Advanced Study (TUM-IAS), TUM (Technische Universität München), Garching 85748, Germany
| | - M. Chiara Manzini
- Department of Pharmacology and Physiology, George Washington University, Washington, District of Columbia 20037, USA
- Department of Integrative Systems Biology, George Washington University, Washington, District of Columbia 20037, USA
| | - Lawrence Shapiro
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032, USA
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University, New York, New York 10032, USA
| |
Collapse
|
11
|
Abstract
The ease of use, robustness, cost-effectiveness, and posttranslational machinery make baculovirus expression system a popular choice for production of eukaryotic membrane proteins. This system can be readily adapted for high-throughput operations. This chapter outlines the techniques and procedures for cloning, transfection, small-scale production, and purification of membrane protein samples in a high-throughput manner.
Collapse
|
12
|
Zheng H, Handing KB, Zimmerman MD, Shabalin IG, Almo SC, Minor W. X-ray crystallography over the past decade for novel drug discovery - where are we heading next? Expert Opin Drug Discov 2015; 10:975-89. [PMID: 26177814 DOI: 10.1517/17460441.2015.1061991] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Macromolecular X-ray crystallography has been the primary methodology for determining the three-dimensional structures of proteins, nucleic acids and viruses. Structural information has paved the way for structure-guided drug discovery and laid the foundations for structural bioinformatics. However, X-ray crystallography still has a few fundamental limitations, some of which may be overcome and complemented using emerging methods and technologies in other areas of structural biology. AREAS COVERED This review describes how structural knowledge gained from X-ray crystallography has been used to advance other biophysical methods for structure determination (and vice versa). This article also covers current practices for integrating data generated by other biochemical and biophysical methods with those obtained from X-ray crystallography. Finally, the authors articulate their vision about how a combination of structural and biochemical/biophysical methods may improve our understanding of biological processes and interactions. EXPERT OPINION X-ray crystallography has been, and will continue to serve as, the central source of experimental structural biology data used in the discovery of new drugs. However, other structural biology techniques are useful not only to overcome the major limitation of X-ray crystallography, but also to provide complementary structural data that is useful in drug discovery. The use of recent advancements in biochemical, spectroscopy and bioinformatics methods may revolutionize drug discovery, albeit only when these data are combined and analyzed with effective data management systems. Accurate and complete data management is crucial for developing experimental procedures that are robust and reproducible.
Collapse
Affiliation(s)
- Heping Zheng
- University of Virginia, Department of Molecular Physiology and Biological Physics , 1340 Jefferson Park Avenue, Charlottesville, VA 22908 , USA +1 434 243 6865 ; +1 434 243 2981 ;
| | | | | | | | | | | |
Collapse
|
13
|
Thomas JA, Tate CG. Quality control in eukaryotic membrane protein overproduction. J Mol Biol 2015; 426:4139-4154. [PMID: 25454020 PMCID: PMC4271737 DOI: 10.1016/j.jmb.2014.10.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 10/12/2014] [Accepted: 10/13/2014] [Indexed: 10/25/2022]
Abstract
The overexpression of authentically folded eukaryotic membrane proteins in milligramme quantities is a fundamental prerequisite for structural studies. One of the most commonly used expression systems for the production of mammalian membrane proteins is the baculovirus expression system in insect cells. However, a detailed analysis by radioligand binding and comparative Western blotting of G protein-coupled receptors and a transporter produced in insect cells showed that a considerable proportion of the expressed protein was misfolded and incapable of ligand binding. In contrast, production of the same membrane proteins in stable inducible mammalian cell lines suggested that the majority was folded correctly. It was noted that detergent solubilisation of the misfolded membrane proteins using either digitonin or dodecylmaltoside was considerablyless efficient than using sodium dodecyl sulfate or foscholine-12, whilst these detergents were equally efficient at solubilising correctly folded membrane proteins. This provides a simple and rapid test to suggest whether heterologously expressed mammalian membrane proteins are indeed correctly folded, without requiring radioligand binding assays. This will greatly facilitate the high-throughput production of fully functional membrane proteins for structural studies.
Collapse
Affiliation(s)
- Jennifer A Thomas
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Christopher G Tate
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK.
| |
Collapse
|
14
|
Geertsma ER. FX cloning: a simple and robust high-throughput cloning method for protein expression. Methods Mol Biol 2014; 1116:153-64. [PMID: 24395363 DOI: 10.1007/978-1-62703-764-8_11] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The immense amount of gene sequences available nowadays allows scientist to screen broadly for extraordinary proteins. Reliable cloning tools that allow the parallel processing of many targets are vital for the success of this strategy. The FX cloning procedure detailed here is such a straightforward and efficient tool. It is dedicated to the cloning of open reading frames (ORFs) with the final aim of expressing the corresponding proteins. FX cloning combines attractive features of established high-throughput cloning methods that were thus far not unified in one single method. It facilitates the subcloning of a sequence-verified ORF to a variety of expression vectors, but is sufficiently versatile to accept PCR products as well. Moreover, the common, but undesirable feature of extending target ORFs with long cloning-related sequences is avoided. It leads to the addition of only one amino acid to each side of the protein. As a consequence, only one primer pair or PCR product suffices to generate expression vectors for both N- and C-terminal translational fusions. FX cloning is highly efficient and economical in its use. The method is suited for high-throughput cloning projects and also for everyday cloning of single targets. FX cloning is based on the use of type IIS restriction enzymes and negative selection markers. The full procedure takes place in one pot in less than 3 h and does not require intermediate purification steps nor extensive handling. The method has proven to be very robust and suitable for all common expression systems.
Collapse
Affiliation(s)
- Eric R Geertsma
- Institute of Biochemistry, Biocenter N220, Goethe-University Frankfurt, Frankfurt/M., Germany
| |
Collapse
|
15
|
Sciara G, Clarke OB, Tomasek D, Kloss B, Tabuso S, Byfield R, Cohn R, Banerjee S, Rajashankar KR, Slavkovic V, Graziano JH, Shapiro L, Mancia F. Structural basis for catalysis in a CDP-alcohol phosphotransferase. Nat Commun 2014; 5:4068. [PMID: 24923293 PMCID: PMC4098843 DOI: 10.1038/ncomms5068] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 05/08/2014] [Indexed: 12/21/2022] Open
Abstract
The CDP-alcohol phosphotransferase (CDP-AP) family of integral membrane enzymes catalyses the transfer of a substituted phosphate group from a CDP-linked donor to an alcohol acceptor. This is an essential reaction for phospholipid biosynthesis across all kingdoms of life, and it is catalysed solely by CDP-APs. Here we report the 2.0 Å resolution crystal structure of a representative CDP-AP from Archaeoglobus fulgidus. The enzyme (AF2299) is a homodimer, with each protomer consisting of six transmembrane helices and an N-terminal cytosolic domain. A polar cavity within the membrane accommodates the active site, lined with the residues from an absolutely conserved CDP-AP signature motif (D(1)xxD(2)G(1)xxAR...G(2)xxxD(3)xxxD(4)). Structures in the apo, CMP-bound, CDP-bound and CDP-glycerol-bound states define functional roles for each of these eight conserved residues and allow us to propose a sequential, base-catalysed mechanism universal for CDP-APs, in which the fourth aspartate (D4) acts as the catalytic base.
Collapse
Affiliation(s)
- Giuliano Sciara
- 1] Department of Physiology and Cellular Biophysics, Columbia University, New York, New York 10032, USA [2]
| | - Oliver B Clarke
- 1] Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032, USA [2]
| | - David Tomasek
- 1] Department of Physiology and Cellular Biophysics, Columbia University, New York, New York 10032, USA [2]
| | - Brian Kloss
- New York Consortium on Membrane Protein Structure, New York Structural Biology Center, 89 Convent Avenue, New York, New York 10027, USA
| | - Shantelle Tabuso
- New York Consortium on Membrane Protein Structure, New York Structural Biology Center, 89 Convent Avenue, New York, New York 10027, USA
| | - Rushelle Byfield
- Department of Physiology and Cellular Biophysics, Columbia University, New York, New York 10032, USA
| | - Raphael Cohn
- Department of Physiology and Cellular Biophysics, Columbia University, New York, New York 10032, USA
| | - Surajit Banerjee
- Department of Chemistry and Chemical Biology, Cornell University, NE-CAT, Advanced Photon Source, Argonne, Illinois 60439, USA
| | - Kanagalaghatta R Rajashankar
- Department of Chemistry and Chemical Biology, Cornell University, NE-CAT, Advanced Photon Source, Argonne, Illinois 60439, USA
| | - Vesna Slavkovic
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032, USA
| | - Joseph H Graziano
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032, USA
| | - Lawrence Shapiro
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032, USA
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University, New York, New York 10032, USA
| |
Collapse
|
16
|
Ma P, Varela F, Magoch M, Silva AR, Rosário AL, Brito J, Oliveira TF, Nogly P, Pessanha M, Stelter M, Kletzin A, Henderson PJF, Archer M. An efficient strategy for small-scale screening and production of archaeal membrane transport proteins in Escherichia coli. PLoS One 2013; 8:e76913. [PMID: 24282478 PMCID: PMC3838208 DOI: 10.1371/journal.pone.0076913] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 08/28/2013] [Indexed: 11/30/2022] Open
Abstract
Background Membrane proteins play a key role in many fundamental cellular processes such as transport of nutrients, sensing of environmental signals and energy transduction, and account for over 50% of all known drug targets. Despite their importance, structural and functional characterisation of membrane proteins still remains a challenge, partially due to the difficulties in recombinant expression and purification. Therefore the need for development of efficient methods for heterologous production is essential. Methodology/Principal Findings Fifteen integral membrane transport proteins from Archaea were selected as test targets, chosen to represent two superfamilies widespread in all organisms known as the Major Facilitator Superfamily (MFS) and the 5-Helix Inverted Repeat Transporter superfamily (5HIRT). These proteins typically have eleven to twelve predicted transmembrane helices and are putative transporters for sugar, metabolite, nucleobase, vitamin or neurotransmitter. They include a wide range of examples from the following families: Metabolite-H+-symporter; Sugar Porter; Nucleobase-Cation-Symporter-1; Nucleobase-Cation-Symporter-2; and neurotransmitter-sodium-symporter. Overproduction of transporters was evaluated with three vectors (pTTQ18, pET52b, pWarf) and two Escherichia coli strains (BL21 Star and C43 (DE3)). Thirteen transporter genes were successfully expressed; only two did not express in any of the tested vector-strain combinations. Initial trials showed that seven transporters could be purified and six of these yielded quantities of ≥ 0.4 mg per litre suitable for functional and structural studies. Size-exclusion chromatography confirmed that two purified transporters were almost homogeneous while four others were shown to be non-aggregating, indicating that they are ready for up-scale production and crystallisation trials. Conclusions/Significance Here, we describe an efficient strategy for heterologous production of membrane transport proteins in E. coli. Small-volume cultures (10 mL) produced sufficient amount of proteins to assess their purity and aggregation state. The methods described in this work are simple to implement and can be easily applied to many more membrane proteins.
Collapse
Affiliation(s)
- Pikyee Ma
- Instituto de Tecnologia Quίmica e Biolόgica, Universidade Nova de Lisboa, Oeiras, Portugal
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Optimizing Membrane Protein Overexpression in the Escherichia coli strain Lemo21(DE3). J Mol Biol 2012; 423:648-59. [DOI: 10.1016/j.jmb.2012.07.019] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 07/20/2012] [Accepted: 07/24/2012] [Indexed: 11/19/2022]
|
18
|
Abstract
The number of structures of integral membrane proteins from higher eukaryotes is steadily increasing due to a number of innovative protein engineering and crystallization strategies devised over the last few years. However, it is sobering to reflect that these structures represent only a tiny proportion of the total number of membrane proteins encoded by a mammalian genome. In addition, the structures determined to date are of the most tractable membrane proteins, i.e., those that are expressed functionally and to high levels in yeast or in insect cells using the baculovirus expression system. However, some membrane proteins that are expressed inefficiently in these systems can be produced at sufficiently high levels in mammalian cells to allow structure determination. Mammalian expression systems are an under-used resource in structural biology and represent an effective way to produce fully functional membrane proteins for structural studies. This review will discuss examples of vertebrate membrane protein overexpression in mammalian cells using a variety of viral, constitutive or inducible expression systems.
Collapse
Affiliation(s)
- Juni Andréll
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | | |
Collapse
|
19
|
Kloppmann E, Punta M, Rost B. Structural genomics plucks high-hanging membrane proteins. Curr Opin Struct Biol 2012; 22:326-32. [PMID: 22622032 DOI: 10.1016/j.sbi.2012.05.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2012] [Revised: 03/28/2012] [Accepted: 05/01/2012] [Indexed: 01/21/2023]
Abstract
Recent years have seen the establishment of structural genomics centers that explicitly target integral membrane proteins. Here, we review the advances in targeting these extremely high-hanging fruits of structural biology in high-throughput mode. We observe that the experimental determination of high-resolution structures of integral membrane proteins is increasingly successful both in terms of getting structures and of covering important protein families, for example, from Pfam. Structural genomics has begun to contribute significantly toward this progress. An important component of this contribution is the set up of robotic pipelines that generate a wealth of experimental data for membrane proteins. We argue that prediction methods for the identification of membrane regions and for the comparison of membrane proteins largely suffice to meet the challenges of target selection for structural genomics of membrane proteins. In contrast, we need better methods to prioritize the most promising members in a family of closely related proteins and to annotate protein function from sequence and structure in absence of homology.
Collapse
Affiliation(s)
- Edda Kloppmann
- Department of Bioinformatics and Computational Biology, Technical University Munich, Germany.
| | | | | |
Collapse
|
20
|
Abstract
Membrane proteins (MPs) mediate important physiological processes for the cell via extracellular and intracellular interactions. To better understand the biochemical and structural bases of these interactions, well-characterized preparations of purified MPs are required. This introduction reviews common problems encountered in MP preparation.
Collapse
Affiliation(s)
- Mark L Chiu
- Biologics Research, Biotechnology Center of Excellence, Janssen Research & Development, Radnor, Pennsylvania, USA
| |
Collapse
|
21
|
Transient transfection coupled to baculovirus infection for rapid protein expression screening in insect cells. J Struct Biol 2012; 179:46-55. [PMID: 22580066 DOI: 10.1016/j.jsb.2012.04.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Revised: 04/20/2012] [Accepted: 04/24/2012] [Indexed: 12/13/2022]
Abstract
Baculovirus infected insect cells are widely used for heterologous protein expression. Despite the power of this system, the use of baculovirus techniques for protein expression screening is hampered by the time and resources needed to generate each recombinant baculovirus. Here, we show that a transfection/infection based expression system is suitable for screening of expression constructs in insect cells and represents a valid alternative to other traditional screening methodologies using recombinant baculovirus. The described method is based on gene delivery by transfection coupled to the induction of protein expression by non-recombinant baculovirus infection. Vectors that control expression by a combination of the baculovirus promoters ie1 and p10 and the enhancer element hr5 are among the ones suitable for this method. Infection with non-recombinant baculovirus drastically increases the basal activity of these elements, leading to protein over-expression. Multiple vectors can be simultaneously co-transfected/infected, making transfection/infection amenable for screening of multiple co-expressed proteins and protein complexes. Taken together, our results prove that the transfection/infection protocol is a valid and innovative approach for increasing speed and reducing costs of protein expression screening for structural and functional studies.
Collapse
|
22
|
Sciara G, Mancia F. Highlights from recently determined structures of membrane proteins: a focus on channels and transporters. Curr Opin Struct Biol 2012; 22:476-81. [PMID: 22472602 DOI: 10.1016/j.sbi.2012.03.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 03/09/2012] [Accepted: 03/14/2012] [Indexed: 12/23/2022]
Abstract
After decades of absent or lackluster growth, recent years have at long last witnessed an exponential growth in the number of novel membrane protein structures determined. Every single achievement has had a tremendous impact on the scientific community, providing an unprecedented wealth of information that typically only an atomic resolution structure can contribute to our molecular understanding of how a protein functions. Presented here is a review of some of the most exciting novel structures of channels and transporters determined by X-ray crystallography in the last two years, and a discussion of their analogies, differences and mechanistic implications.
Collapse
Affiliation(s)
- Giuliano Sciara
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | | |
Collapse
|
23
|
Castell OK, Berridge J, Wallace MI. Quantification of Membrane Protein Inhibition by Optical Ion Flux in a Droplet Interface Bilayer Array. Angew Chem Int Ed Engl 2012; 51:3134-8. [DOI: 10.1002/anie.201107343] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 01/24/2012] [Indexed: 01/01/2023]
|
24
|
Castell OK, Berridge J, Wallace MI. Quantification of Membrane Protein Inhibition by Optical Ion Flux in a Droplet Interface Bilayer Array. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201107343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|