1
|
Masoumzadeh E, Ying J, Baber JL, Anfinrud P, Bax A. Proline Peptide Bond Isomerization in Ubiquitin Under Folding and Denaturing Conditions by Pressure-Jump NMR. J Mol Biol 2024; 436:168587. [PMID: 38663546 DOI: 10.1016/j.jmb.2024.168587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 04/16/2024] [Accepted: 04/17/2024] [Indexed: 05/07/2024]
Abstract
Proline isomerization is widely recognized as a kinetic bottleneck in protein folding, amplified for proteins rich in Pro residues. We introduced repeated hydrostatic pressure jumps between native and pressure-denaturing conditions inside an NMR sample cell to study proline isomerization in the pressure-sensitized L50A ubiquitin mutant. Whereas in two unfolded heptapeptides, X-Pro peptide bonds isomerized ca 1.6-fold faster at 1 bar than at 2.5 kbar, for ubiquitin ca eight-fold faster isomerization was observed for Pro-38 and ca two-fold for Pro-19 and Pro-37 relative to rates measured in the pressure-denatured state. Activation energies for isomerization in pressure-denatured ubiquitin were close to literature values of 20 kcal/mole for denatured polypeptides but showed a substantial drop to 12.7 kcal/mole for Pro-38 at atmospheric pressure. For ubiquitin isomers with a cis E18-P19 peptide bond, the 1-bar NMR spectrum showed sharp resonances with near random coil chemical shifts for the C-terminal half of the protein, characteristic of an unfolded chain, while most of the N-terminal residues were invisible due to exchange broadening, pointing to a metastable partially folded state for this previously recognized 'folding nucleus'. For cis-P37 isomers, a drop in pressure resulted in the rapid loss of nearly all unfolded-state NMR resonances, while the recovery of native state intensity revealed a slow component attributed to cis → trans isomerization of P37. This result implies that the NMR-invisible cis-P37 isomer adopts a molten globule state that encompasses the entire length of the ubiquitin chain, suggestive of a structure that mostly resembles the folded state.
Collapse
Affiliation(s)
- Elahe Masoumzadeh
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - James L Baber
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Philip Anfinrud
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
| |
Collapse
|
2
|
Gelenter MD, Yau WM, Anfinrud PA, Bax A. From Milliseconds to Minutes: Melittin Self-Assembly from Concerted Non-Equilibrium Pressure-Jump and Equilibrium Relaxation Nuclear Magnetic Resonance. J Phys Chem Lett 2024; 15:1930-1935. [PMID: 38346015 PMCID: PMC10896212 DOI: 10.1021/acs.jpclett.3c03563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/25/2024] [Accepted: 01/29/2024] [Indexed: 02/23/2024]
Abstract
Non-equilibrium kinetics techniques like pressure-jump nuclear magnetic resonance (NMR) are powerful in tracking changes in oligomeric populations and are not limited by relaxation rates for the time scales of exchange that can be probed. However, these techniques are less sensitive to minor, transient populations than are Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion experiments. We integrated non-equilibrium pressure-jump and equilibrium CPMG relaxation dispersion data to fully map the kinetic landscape of melittin tetramerization. While monomeric peptides weakly form dimers (Kd,D/M ≈ 26 mM) whose population never exceeds 1.6% at 288 K, dimers associate tightly to form stable tetrameric species (Kd,T/D ≈ 740 nM). Exchange between the monomer and dimer, along with exchange between the dimer and tetramer, occurs on the millisecond time scale. The NMR approach developed herein can be readily applied to studying the folding and misfolding of a wide range of oligomeric assemblies.
Collapse
Affiliation(s)
- Martin D Gelenter
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 5 Memorial Drive, Bethesda, Maryland 20892, United States
| | - Wai-Ming Yau
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 5 Memorial Drive, Bethesda, Maryland 20892, United States
| | - Philip A Anfinrud
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 5 Memorial Drive, Bethesda, Maryland 20892, United States
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 5 Memorial Drive, Bethesda, Maryland 20892, United States
| |
Collapse
|
3
|
Chiliveri SC, Shen Y, Baber JL, Ying J, Sagar V, Wistow G, Anfinrud P, Bax A. Experimental NOE, Chemical Shift, and Proline Isomerization Data Provide Detailed Insights into Amelotin Oligomerization. J Am Chem Soc 2023; 145:18063-18074. [PMID: 37548612 PMCID: PMC10436275 DOI: 10.1021/jacs.3c05710] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Indexed: 08/08/2023]
Abstract
Amelotin is an intrinsically disordered protein (IDP) rich in Pro residues and is involved in hydroxyapatite mineralization. It rapidly oligomerizes under physiological conditions of pH and pressure but reverts to its monomeric IDP state at elevated pressure. We identified a 105-residue segment of the protein that becomes ordered upon oligomerization, and we used pressure-jump NMR spectroscopy to measure long-range NOE contacts that exist exclusively in the oligomeric NMR-invisible state. The kinetics of oligomerization and dissociation were probed at the residue-specific level, revealing that the oligomerization process is initiated in the C-terminal half of the segment. Using pressure-jump NMR, the degree of order in the oligomer at the sites of Pro residues was probed by monitoring changes in cis/trans equilibria relative to the IDP state after long-term equilibration under oligomerizing conditions. Whereas most Pro residues revert to trans in the oligomeric state, Pro-49 favors a cis configuration and three Pro residues retain an unchanged cis fraction, pointing to their local lack of order in the oligomeric state. NOE contacts and secondary 13C chemical shifts in the oligomeric state indicate the presence of an 11-residue α-helix, preceded by a small intramolecular antiparallel β-sheet, with slower formation of long-range intermolecular interactions to N-terminal residues. Although none of the models generated by AlphaFold2 for the amelotin monomer was consistent with experimental data, subunits of a hexamer generated by AlphaFold-Multimer satisfied intramolecular NOE and chemical shift data and may provide a starting point for developing atomic models for the oligomeric state.
Collapse
Affiliation(s)
- Sai Chaitanya Chiliveri
- Laboratory
of Chemical Physics, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United States
| | - Yang Shen
- Laboratory
of Chemical Physics, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United States
| | - James L. Baber
- Laboratory
of Chemical Physics, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United States
| | - Jinfa Ying
- Laboratory
of Chemical Physics, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United States
| | - Vatsala Sagar
- Section
on Molecular Structure and Function, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Graeme Wistow
- Section
on Molecular Structure and Function, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Philip Anfinrud
- Laboratory
of Chemical Physics, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United States
| | - Ad Bax
- Laboratory
of Chemical Physics, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United States
| |
Collapse
|
4
|
Shen Y, Bax A. Synergism between x-ray crystallography and NMR residual dipolar couplings in characterizing protein dynamics. Struct Dyn 2023; 10:040901. [PMID: 37448874 PMCID: PMC10338066 DOI: 10.1063/4.0000192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 06/23/2023] [Indexed: 07/15/2023]
Abstract
The important role of structural dynamics in protein function is widely recognized. Thermal or B-factors and their anisotropy, seen in x-ray analysis of protein structures, report on the presence of atomic coordinate heterogeneity that can be attributed to motion. However, their quantitative evaluation in terms of protein dynamics by x-ray ensemble refinement remains challenging. NMR spectroscopy provides quantitative information on the amplitudes and time scales of motional processes. Unfortunately, with a few exceptions, the NMR data do not provide direct insights into the atomic details of dynamic trajectories. Residual dipolar couplings, measured by solution NMR, are very precise parameters reporting on the time-averaged bond-vector orientations and may offer the opportunity to derive correctly weighted dynamic ensembles of structures for cases where multiple high-resolution x-ray structures are available. Applications to the SARS-CoV-2 main protease, Mpro, and ubiquitin highlight this complementarity of NMR and crystallography for quantitative assessment of internal motions.
Collapse
Affiliation(s)
| | - Ad Bax
- Author to whom correspondence should be addressed:
| |
Collapse
|
5
|
Shen Y, Robertson AJ, Bax A. Validation of X-ray Crystal Structure Ensemble Representations of SARS-CoV-2 Main Protease by Solution NMR Residual Dipolar Couplings. J Mol Biol 2023; 435:168067. [PMID: 37330294 PMCID: PMC10270724 DOI: 10.1016/j.jmb.2023.168067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 03/23/2023] [Accepted: 03/25/2023] [Indexed: 06/19/2023]
Abstract
Considerable debate has focused on whether sampling of molecular dynamics trajectories restrained by crystallographic data can be used to develop realistic ensemble models for proteins in their natural, solution state. For the SARS-CoV-2 main protease, Mpro, we evaluated agreement between solution residual dipolar couplings (RDCs) and various recently reported multi-conformer and dynamic-ensemble crystallographic models. Although Phenix-derived ensemble models showed only small improvements in crystallographic Rfree, substantially improved RDC agreement over fits to a conventionally refined 1.2-Å X-ray structure was observed, in particular for residues with above average disorder in the ensemble. For a set of six lower resolution (1.55-2.19 Å) Mpro X-ray ensembles, obtained at temperatures ranging from 100 to 310 K, no significant improvement over conventional two-conformer representations was found. At the residue level, large differences in motions were observed among these ensembles, suggesting high uncertainties in the X-ray derived dynamics. Indeed, combining the six ensembles from the temperature series with the two 1.2-Å X-ray ensembles into a single 381-member "super ensemble" averaged these uncertainties and substantially improved agreement with RDCs. However, all ensembles showed excursions that were too large for the most dynamic fraction of residues. Our results suggest that further improvements to X-ray ensemble refinement are feasible, and that RDCs provide a sensitive benchmark in such endeavors. Remarkably, a weighted ensemble of 350 PDB Mpro X-ray structures provided slightly better cross-validated agreement with RDCs than any individual ensemble refinement, implying that differences in lattice confinement also limit the fit of RDCs to X-ray coordinates.
Collapse
Affiliation(s)
- Yang Shen
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Angus J Robertson
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA. https://twitter.com/angusjrobertson
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
| |
Collapse
|
6
|
Park SB, Khan M, Chiliveri SC, Hu X, Irvin P, Leek M, Grieshaber A, Hu Z, Jang ES, Bax A, Liang TJ. SARS-CoV-2 omicron variants harbor spike protein mutations responsible for their attenuated fusogenic phenotype. Commun Biol 2023; 6:556. [PMID: 37225764 DOI: 10.1038/s42003-023-04923-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 05/08/2023] [Indexed: 05/26/2023] Open
Abstract
Since the emergence of the Omicron variants at the end of 2021, they quickly became the dominant variants globally. The Omicron variants may be more easily transmitted compared to the earlier Wuhan and the other variants. In this study, we aimed to elucidate mechanisms of the altered infectivity associated with the Omicron variants. We systemically evaluated mutations located in the S2 sequence of spike and identified mutations that are responsible for altered viral fusion. We demonstrated that mutations near the S1/S2 cleavage site decrease S1/S2 cleavage, resulting in reduced fusogenicity. Mutations in the HR1 and other S2 sequences also affect cell-cell fusion. Based on nuclear magnetic resonance (NMR) studies and in silico modeling, these mutations affect fusogenicity possibly at multiple steps of the viral fusion. Our findings reveal that the Omicron variants have accumulated mutations that contribute to reduced syncytial formation and hence an attenuated pathogenicity.
Collapse
Affiliation(s)
- Seung Bum Park
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Mohsin Khan
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Sai Chaitanya Chiliveri
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Xin Hu
- National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, 20850, USA
| | - Parker Irvin
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Madeleine Leek
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Ailis Grieshaber
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Zongyi Hu
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Eun Sun Jang
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, 20892, USA
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, 13620, Republic of Korea
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, 20892, USA
| | - T Jake Liang
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, 20892, USA.
| |
Collapse
|
7
|
Gelenter M, Bax A. Recombinant Expression and Chemical Amidation of Isotopically Labeled Native Melittin. J Am Chem Soc 2023; 145:3850-3854. [PMID: 36753641 PMCID: PMC9951214 DOI: 10.1021/jacs.2c12631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Indexed: 02/10/2023]
Abstract
Post-translational modifications are ubiquitous in the eukaryotic proteome. However, these modifications are rarely incorporated in NMR studies of eukaryotic proteins, which are typically produced through recombinant expression in E. coli. Melittin is the primary peptide in honey bee venom. Its native C-terminal amide significantly affects its equilibrium structure and dynamics in solution and is thus a prerequisite for studying its native structure and function. Here, we present a method for producing triply isotopically labeled (2H, 13C, and 15N) native melittin through recombinant expression followed by chemical amidation. We then show that structural models produced with AlphaFold-Multimer are in even better agreement with experimental residual dipolar couplings than the 2.0 Å resolution X-ray crystal structure for residues G3-K23.
Collapse
Affiliation(s)
- Martin
D. Gelenter
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
| | - Ad Bax
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
| |
Collapse
|
8
|
Berg H, Wirtz Martin MA, Altincekic N, Alshamleh I, Kaur Bains J, Blechar J, Ceylan B, de Jesus V, Dhamotharan K, Fuks C, Gande SL, Hargittay B, Hohmann KF, Hutchinson MT, Korn SM, Krishnathas R, Kutz F, Linhard V, Matzel T, Meiser N, Niesteruk A, Pyper DJ, Schulte L, Trucks S, Azzaoui K, Blommers MJJ, Gadiya Y, Karki R, Zaliani A, Gribbon P, Almeida MDS, Anobom CD, Bula AL, Buetikofer M, Caruso ÍP, Felli IC, Da Poian AT, de Amorim GC, Fourkiotis NK, Gallo A, Ghosh D, Gomes-Neto F, Gorbatyuk O, Hao B, Kurauskas V, Lecoq L, Li Y, Mebus-Antunes NC, Mompean M, Neves-Martins TC, Ninot-Pedrosa M, Pinheiro AS, Pontoriero L, Pustovalova Y, Riek R, Robertson A, Abi Saad MJ, Treviño MA, Tsika AC, Almeida FC, Bax A, Henzler-Wildman K, Hoch JC, Jaudzems K, Laurents DV, Orts J, Pieratelli R, Spyroulias GA, Duchardt-Ferner E, Ferner J, Fuertig B, Hengesbach M, Löhr F, Qureshi N, Richter C, Saxena K, Schlundt A, Sreeramulu S, Wacker A, Weigand JE, Wirmer-Bartoschek J, Woehnert J, Schwalbe H. Comprehensive Fragment Screening of the SARS‐CoV‐2 Proteome Explores Novel Chemical Space for Drug Development. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202205858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Hannes Berg
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | | | - Nadide Altincekic
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Islam Alshamleh
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Jasleen Kaur Bains
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Julius Blechar
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Betül Ceylan
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Vanessa de Jesus
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | | | - Christin Fuks
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Santosh L. Gande
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Bruno Hargittay
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | | | - Marie T. Hutchinson
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | | | - Robin Krishnathas
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Felicitas Kutz
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Verena Linhard
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Tobias Matzel
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Nathalie Meiser
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Anna Niesteruk
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Dennis J. Pyper
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Linda Schulte
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Sven Trucks
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Kamal Azzaoui
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Marcel J J Blommers
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Yojana Gadiya
- Fraunhofer Institute for Molecular Biology and Applied Ecology ScreeningPort: Fraunhofer-Institut fur Translationale Medizin und Pharmakologie ITMP Drug Discovery Research ScreeningPort Screening Unit GERMANY
| | - Reagon Karki
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP: Fraunhofer-Institut fur Translationale Medizin und Pharmakologie ITMP Screening Unit GERMANY
| | - Andrea Zaliani
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP: Fraunhofer-Institut fur Translationale Medizin und Pharmakologie ITMP Screening Unit GERMANY
| | - Philip Gribbon
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP: Fraunhofer-Institut fur Translationale Medizin und Pharmakologie ITMP Screening Unit GERMANY
| | - Marcius da Silva Almeida
- Federal University of Rio de Janeiro: Universidade Federal do Rio de Janeiro Institue for Medical Biochemistry BRAZIL
| | - Cristiane Dinis Anobom
- Federal University of Rio de Janeiro: Universidade Federal do Rio de Janeiro Department of Biochemistry BRAZIL
| | - Anna Lina Bula
- Latvian Institute of Organic Synthesis: Latvijas Organiskas sintezes instituts Institute of Organic Synthesis LATVIA
| | - Matthias Buetikofer
- ETH Zurich: Eidgenossische Technische Hochschule Zurich Institute für Physikalische Chemie GERMANY
| | - Ícaro Putinhon Caruso
- Sao Paulo State University Julio de Mesquita Filho: Universidade Estadual Paulista Julio de Mesquita Filho Department of Physics BRAZIL
| | - Isabella Caterina Felli
- University of Florence: Universita degli Studi di Firenze Magnetic Resonance Center (CERM) ITALY
| | - Andrea T Da Poian
- Sao Paulo State University Julio de Mesquita Filho: Universidade Estadual Paulista Julio de Mesquita Filho Department of Physics GERMANY
| | - Gisele Cardoso de Amorim
- Federal University of Rio de Janeiro: Universidade Federal do Rio de Janeiro Multidisciplinary Center for Research in Biology BRAZIL
| | - Nikolaos K Fourkiotis
- University of Patras - Patras Campus: Panepistemio Patron Department of Pharmacy GREECE
| | - Angelo Gallo
- University of Patras - Patras Campus: Panepistemio Patron Department of Pharmacy GREECE
| | - Dhiman Ghosh
- ETH Zurich: Eidgenossische Technische Hochschule Zurich Institute for Physical Chemistry SWITZERLAND
| | | | - Oksana Gorbatyuk
- UConn Health Department of Molecular Biology and Biophysics UNITED STATES
| | - Bing Hao
- UConn Health Department of Molecular Biology and Biopyhsics UNITED STATES
| | - Vilius Kurauskas
- UW Madison: University of Wisconsin Madison Department of Biochemistry UNITED STATES
| | - Lauriane Lecoq
- Universite de Lyon Molecular Microbiology and Structural Biochemistry FRANCE
| | - Yunfeng Li
- UConn Health Department of Molecular Biology and Biophysics UNITED STATES
| | - Nathane Cunha Mebus-Antunes
- Federal University of Rio de Janeiro: Universidade Federal do Rio de Janeiro Institute of Medical Biochemistry BRAZIL
| | - Miguel Mompean
- Estacion Biologica de Donana CSIC "Rocasolano" Institute for Physical Chemistry SPAIN
| | - Thais Cristtina Neves-Martins
- Federal University of Rio de Janeiro: Universidade Federal do Rio de Janeiro Institute of Medical Biochemistry BRAZIL
| | - Marti Ninot-Pedrosa
- Universite Lyon 1 IUT Lyon 1 Molecular Microbiology and Structural Biochemistry FRANCE
| | - Anderson S Pinheiro
- Federal University of Rio de Janeiro: Universidade Federal do Rio de Janeiro Department of Biochemistry BRAZIL
| | - Letizia Pontoriero
- University of Florence: Universita degli Studi di Firenze Center for Magnetic Resonance ITALY
| | - Yulia Pustovalova
- UConn Health Department of Molecular Biology and Biophysics UNITED STATES
| | - Roland Riek
- ETH Zürich: Eidgenossische Technische Hochschule Zurich Institute for Physical Chemistry SWITZERLAND
| | - Angus Robertson
- NIAMDD: National Institute of Diabetes and Digestive and Kidney Diseases Laboratory of Chemical Physics UNITED STATES
| | - Marie Jose Abi Saad
- University of Vienna: Universitat Wien Department of Pharmaceutical Sciences AUSTRIA
| | - Miguel A Treviño
- CSIC: Consejo Superior de Investigaciones Cientificas "Rocasolano" Institute for Physical Chemistry SPAIN
| | - Aikaterini C Tsika
- University of Patras - Patras Campus: Panepistemio Patron Department of Pharmacy GREECE
| | - Fabio C.L. Almeida
- Federal University of Rio de Janeiro: Universidade Federal do Rio de Janeiro Institute of Medical Biochemistry BRAZIL
| | - Ad Bax
- National Institute of Diabetes and Digestive and Kidney Diseases Laboratory of Chemical Physics UNITED STATES
| | | | - Jeffrey C Hoch
- UConn Health Department of Molecular Biology and Biophysics UNITED STATES
| | - Kristaps Jaudzems
- Institute of Organic Synthesis of the Latvian Academy of Sciences: Latvijas Organiskas sintezes instituts Institute for Organic Chemistry LATVIA
| | - Douglas V Laurents
- Estacion Biologica de Donana CSIC "Rocasolano" Institute for Physical Chemistry SPAIN
| | - Julien Orts
- University of Vienna: Universitat Wien Department of Pharmaceutical Sciences AUSTRIA
| | - Roberta Pieratelli
- University of Florence: Universita degli Studi di Firenze Center for Magnetic Resonance ITALY
| | - Georgios A Spyroulias
- University of Patras - Patras Campus: Panepistemio Patron Department of Pharmacy GREECE
| | | | - Jan Ferner
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Boris Fuertig
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Martin Hengesbach
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Frank Löhr
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Nusrat Qureshi
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Christian Richter
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Krishna Saxena
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Andreas Schlundt
- Goethe-Universitat Frankfurt am Main Department for Biosciences GERMANY
| | - Sridhar Sreeramulu
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Anna Wacker
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Julia E Weigand
- TU Darmstadt: Technische Universitat Darmstadt Department of Biology GERMANY
| | | | - Jens Woehnert
- Goethe-Universitat Frankfurt am Main Department of Biological Sciences GERMANY
| | - Harald Schwalbe
- Goethe-Universitat Frankfurt am Main Institut für Organische Chemie und Chemische Biologie Max-von-Laue-Str. 7 60438 Frankfurt GERMANY
| |
Collapse
|
9
|
Berg H, Wirtz Martin MA, Altincekic N, Alshamleh I, Kaur Bains J, Blechar J, Ceylan B, de Jesus V, Dhamotharan K, Fuks C, Gande SL, Hargittay B, Hohmann KF, Hutchinson MT, Korn SM, Krishnathas R, Kutz F, Linhard V, Matzel T, Meiser N, Niesteruk A, Pyper DJ, Schulte L, Trucks S, Azzaoui K, Blommers MJJ, Gadiya Y, Karki R, Zaliani A, Gribbon P, Almeida MDS, Anobom CD, Bula AL, Buetikofer M, Caruso ÍP, Felli IC, Da Poian AT, de Amorim GC, Fourkiotis NK, Gallo A, Ghosh D, Gomes-Neto F, Gorbatyuk O, Hao B, Kurauskas V, Lecoq L, Li Y, Mebus-Antunes NC, Mompean M, Neves-Martins TC, Ninot-Pedrosa M, Pinheiro AS, Pontoriero L, Pustovalova Y, Riek R, Robertson A, Abi Saad MJ, Treviño MA, Tsika AC, Almeida FC, Bax A, Henzler-Wildman K, Hoch JC, Jaudzems K, Laurents DV, Orts J, Pieratelli R, Spyroulias GA, Duchardt-Ferner E, Ferner J, Fuertig B, Hengesbach M, Löhr F, Qureshi N, Richter C, Saxena K, Schlundt A, Sreeramulu S, Wacker A, Weigand JE, Wirmer-Bartoschek J, Woehnert J, Schwalbe H. Comprehensive Fragment Screening of the SARS‐CoV‐2 Proteome Explores Novel Chemical Space for Drug Development. Angew Chem Int Ed Engl 2022; 61:e202205858. [PMID: 36115062 PMCID: PMC9539013 DOI: 10.1002/anie.202205858] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Indexed: 11/17/2022]
Abstract
SARS‐CoV‐2 (SCoV2) and its variants of concern pose serious challenges to the public health. The variants increased challenges to vaccines, thus necessitating for development of new intervention strategies including anti‐virals. Within the international Covid19‐NMR consortium, we have identified binders targeting the RNA genome of SCoV2. We established protocols for the production and NMR characterization of more than 80% of all SCoV2 proteins. Here, we performed an NMR screening using a fragment library for binding to 25 SCoV2 proteins and identified hits also against previously unexplored SCoV2 proteins. Computational mapping was used to predict binding sites and identify functional moieties (chemotypes) of the ligands occupying these pockets. Striking consensus was observed between NMR‐detected binding sites of the main protease and the computational procedure. Our investigation provides novel structural and chemical space for structure‐based drug design against the SCoV2 proteome.
Collapse
Affiliation(s)
- Hannes Berg
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | | | - Nadide Altincekic
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Islam Alshamleh
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Jasleen Kaur Bains
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Julius Blechar
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Betül Ceylan
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Vanessa de Jesus
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | | | - Christin Fuks
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Santosh L. Gande
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Bruno Hargittay
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | | | - Marie T. Hutchinson
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | | | - Robin Krishnathas
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Felicitas Kutz
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Verena Linhard
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Tobias Matzel
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Nathalie Meiser
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Anna Niesteruk
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Dennis J. Pyper
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Linda Schulte
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Sven Trucks
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Kamal Azzaoui
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Marcel J J Blommers
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Yojana Gadiya
- Fraunhofer Institute for Molecular Biology and Applied Ecology ScreeningPort: Fraunhofer-Institut fur Translationale Medizin und Pharmakologie ITMP Drug Discovery Research ScreeningPort Screening Unit GERMANY
| | - Reagon Karki
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP: Fraunhofer-Institut fur Translationale Medizin und Pharmakologie ITMP Screening Unit GERMANY
| | - Andrea Zaliani
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP: Fraunhofer-Institut fur Translationale Medizin und Pharmakologie ITMP Screening Unit GERMANY
| | - Philip Gribbon
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP: Fraunhofer-Institut fur Translationale Medizin und Pharmakologie ITMP Screening Unit GERMANY
| | - Marcius da Silva Almeida
- Federal University of Rio de Janeiro: Universidade Federal do Rio de Janeiro Institue for Medical Biochemistry BRAZIL
| | - Cristiane Dinis Anobom
- Federal University of Rio de Janeiro: Universidade Federal do Rio de Janeiro Department of Biochemistry BRAZIL
| | - Anna Lina Bula
- Latvian Institute of Organic Synthesis: Latvijas Organiskas sintezes instituts Institute of Organic Synthesis LATVIA
| | - Matthias Buetikofer
- ETH Zurich: Eidgenossische Technische Hochschule Zurich Institute für Physikalische Chemie GERMANY
| | - Ícaro Putinhon Caruso
- Sao Paulo State University Julio de Mesquita Filho: Universidade Estadual Paulista Julio de Mesquita Filho Department of Physics BRAZIL
| | - Isabella Caterina Felli
- University of Florence: Universita degli Studi di Firenze Magnetic Resonance Center (CERM) ITALY
| | - Andrea T Da Poian
- Sao Paulo State University Julio de Mesquita Filho: Universidade Estadual Paulista Julio de Mesquita Filho Department of Physics GERMANY
| | - Gisele Cardoso de Amorim
- Federal University of Rio de Janeiro: Universidade Federal do Rio de Janeiro Multidisciplinary Center for Research in Biology BRAZIL
| | - Nikolaos K Fourkiotis
- University of Patras - Patras Campus: Panepistemio Patron Department of Pharmacy GREECE
| | - Angelo Gallo
- University of Patras - Patras Campus: Panepistemio Patron Department of Pharmacy GREECE
| | - Dhiman Ghosh
- ETH Zurich: Eidgenossische Technische Hochschule Zurich Institute for Physical Chemistry SWITZERLAND
| | | | - Oksana Gorbatyuk
- UConn Health Department of Molecular Biology and Biophysics UNITED STATES
| | - Bing Hao
- UConn Health Department of Molecular Biology and Biopyhsics UNITED STATES
| | - Vilius Kurauskas
- UW Madison: University of Wisconsin Madison Department of Biochemistry UNITED STATES
| | - Lauriane Lecoq
- Universite de Lyon Molecular Microbiology and Structural Biochemistry FRANCE
| | - Yunfeng Li
- UConn Health Department of Molecular Biology and Biophysics UNITED STATES
| | - Nathane Cunha Mebus-Antunes
- Federal University of Rio de Janeiro: Universidade Federal do Rio de Janeiro Institute of Medical Biochemistry BRAZIL
| | - Miguel Mompean
- Estacion Biologica de Donana CSIC "Rocasolano" Institute for Physical Chemistry SPAIN
| | - Thais Cristtina Neves-Martins
- Federal University of Rio de Janeiro: Universidade Federal do Rio de Janeiro Institute of Medical Biochemistry BRAZIL
| | - Marti Ninot-Pedrosa
- Universite Lyon 1 IUT Lyon 1 Molecular Microbiology and Structural Biochemistry FRANCE
| | - Anderson S Pinheiro
- Federal University of Rio de Janeiro: Universidade Federal do Rio de Janeiro Department of Biochemistry BRAZIL
| | - Letizia Pontoriero
- University of Florence: Universita degli Studi di Firenze Center for Magnetic Resonance ITALY
| | - Yulia Pustovalova
- UConn Health Department of Molecular Biology and Biophysics UNITED STATES
| | - Roland Riek
- ETH Zürich: Eidgenossische Technische Hochschule Zurich Institute for Physical Chemistry SWITZERLAND
| | - Angus Robertson
- NIAMDD: National Institute of Diabetes and Digestive and Kidney Diseases Laboratory of Chemical Physics UNITED STATES
| | - Marie Jose Abi Saad
- University of Vienna: Universitat Wien Department of Pharmaceutical Sciences AUSTRIA
| | - Miguel A Treviño
- CSIC: Consejo Superior de Investigaciones Cientificas "Rocasolano" Institute for Physical Chemistry SPAIN
| | - Aikaterini C Tsika
- University of Patras - Patras Campus: Panepistemio Patron Department of Pharmacy GREECE
| | - Fabio C.L. Almeida
- Federal University of Rio de Janeiro: Universidade Federal do Rio de Janeiro Institute of Medical Biochemistry BRAZIL
| | - Ad Bax
- National Institute of Diabetes and Digestive and Kidney Diseases Laboratory of Chemical Physics UNITED STATES
| | | | - Jeffrey C Hoch
- UConn Health Department of Molecular Biology and Biophysics UNITED STATES
| | - Kristaps Jaudzems
- Institute of Organic Synthesis of the Latvian Academy of Sciences: Latvijas Organiskas sintezes instituts Institute for Organic Chemistry LATVIA
| | - Douglas V Laurents
- Estacion Biologica de Donana CSIC "Rocasolano" Institute for Physical Chemistry SPAIN
| | - Julien Orts
- University of Vienna: Universitat Wien Department of Pharmaceutical Sciences AUSTRIA
| | - Roberta Pieratelli
- University of Florence: Universita degli Studi di Firenze Center for Magnetic Resonance ITALY
| | - Georgios A Spyroulias
- University of Patras - Patras Campus: Panepistemio Patron Department of Pharmacy GREECE
| | | | - Jan Ferner
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Boris Fuertig
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Martin Hengesbach
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Frank Löhr
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Nusrat Qureshi
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Christian Richter
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Krishna Saxena
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Andreas Schlundt
- Goethe-Universitat Frankfurt am Main Department for Biosciences GERMANY
| | - Sridhar Sreeramulu
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Anna Wacker
- Goethe-Universitat Frankfurt am Main Biochemistry, Chemistry, Pharmacy GERMANY
| | - Julia E Weigand
- TU Darmstadt: Technische Universitat Darmstadt Department of Biology GERMANY
| | | | - Jens Woehnert
- Goethe-Universitat Frankfurt am Main Department of Biological Sciences GERMANY
| | - Harald Schwalbe
- Goethe-Universitat Frankfurt am Main Institut für Organische Chemie und Chemische Biologie Max-von-Laue-Str. 7 60438 Frankfurt GERMANY
| |
Collapse
|
10
|
Chiliveri SC, Louis JM, Best RB, Bax A. Real-time Exchange of the Lipid-bound Intermediate and Post-fusion States of the HIV-1 gp41 Ectodomain. J Mol Biol 2022; 434:167683. [PMID: 35700771 PMCID: PMC9378563 DOI: 10.1016/j.jmb.2022.167683] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 06/03/2022] [Accepted: 06/08/2022] [Indexed: 11/17/2022]
Abstract
The envelope glycoprotein gp41 of the HIV-1 virus mediates its entry into the host cell. During this process, gp41 undergoes large conformational changes and the energy released in the remodeling events is utilized to overcome the barrier associated with fusing the viral and host membranes. Although the structural intermediates of this fusion process are attractive targets for drug development, no detailed high-resolution structural information or quantitative thermodynamic characterization are available. By measuring the dynamic equilibrium between the lipid-bound intermediate and the post-fusion six-helical bundle (6HB) states of the gp41 ectodomain in the presence of bilayer membrane mimetics, we derived both the reaction kinetics and energies associated with these two states by solution NMR spectroscopy. At equilibrium, an exchange time constant of about 12 seconds at 38 °C is observed, and the post-fusion conformation is energetically more stable than the lipid-bound state by 3.4 kcal mol-1. The temperature dependence of the kinetics indicates that the folding occurs through a high-energy transition state which may resemble a 5HB structure. The energetics and kinetics of gp41 folding in the context of membrane bilayers provide a molecular basis for an improved understanding of viral membrane fusion.
Collapse
Affiliation(s)
- Sai Chaitanya Chiliveri
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA. https://twitter.com/SaiChiliveri
| | - John M Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Robert B Best
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
| |
Collapse
|
11
|
Robertson AJ, Ying J, Bax A. NMR Observation of Sulfhydryl Signals in SARS-CoV-2 Main Protease Aids Structural Studies. Chembiochem 2022; 23:e202200471. [PMID: 35972230 PMCID: PMC9537880 DOI: 10.1002/cbic.202200471] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 08/15/2022] [Indexed: 11/24/2022]
Abstract
The 68‐kDa homodimeric 3C‐like protease of SARS‐CoV‐2, Mpro (3CLpro/Nsp5), is a key antiviral drug target. NMR spectroscopy of this large system proved challenging and resonance assignments have remained incomplete. Here we present the near‐complete (>97 %) backbone assignments of a C145A variant of Mpro (MproC145A) both with, and without, the N‐terminal auto‐cleavage substrate sequence, in its native homodimeric state. We also present SILLY (Selective Inversion of thioL and Ligand for NOESY), a simple yet effective pseudo‐3D NMR experiment that utilizes NOEs to identify interactions between Cys‐thiol or aliphatic protons, and their spatially proximate backbone amides in a perdeuterated protein background. High protection against hydrogen exchange is observed for 10 of the 11 thiol groups in MproC145A, even those that are partially accessible to solvent. A combination of SILLY methods and high‐resolution triple‐resonance NMR experiments reveals site‐specific interactions between Mpro, its substrate peptides, and other ligands, which present opportunities for competitive binding studies in future drug design efforts.
Collapse
Affiliation(s)
- Angus J Robertson
- National Institute of Diabetes and Digestive and Kidney Diseases, Laboratory of Chemical Physics, UNITED STATES
| | - Jinfa Ying
- National Institute of Diabetes and Digestive and Kidney Diseases, Laboratory of Chemical Physics, UNITED STATES
| | - Ad Bax
- Nat. Inst. Diabetes, Laboratory Chem. Phys., Building 5, Rm 126, 20892, Bethesda, UNITED STATES
| |
Collapse
|
12
|
Abstract
![]()
Due
to similar reactivity of organic hydroperoxides (OHPs), an
HPLC separation step is typically required for their indirect (chemical)
quantification in mixtures. The high sensitivity of chemical shifts
to chemical structure makes NMR an ideal tool for the simultaneous
quantification of OHPs in mixtures, but the concentration of these
analytes in the samples of interest is usually well below the sensitivity
of standard NMR experiments. This sensitivity problem can be mitigated
by taking advantage of the fact that the z magnetization
of the H2O2 resonance recovers at the rate of
hydrogen exchange with water, which is significantly faster than longitudinal
relaxation, thus enabling very fast scanning for signal-to-noise enhancement.
An adaptation of the E-BURP2 pulse is described that
suppresses the water signal by more than 4 orders of magnitude, yielding
uniform excitation of peroxide signals without interference of the
ca. 108-fold stronger H2O resonance. We demonstrate
the method for a mixture of OHPs and report the chemical shifts for
multiple OHPs that are of interest in atmospheric chemistry. As shown
for hydroxymethyl hydroperoxide, the chemical decay of OHPs can be
tracked directly by NMR spectroscopy.
Collapse
Affiliation(s)
- Tayeb Kakeshpour
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Ad Bax
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, United States
| |
Collapse
|
13
|
Abstract
Quantification of H2O2 concentration in aqueous solutions is of interest in many fields. It usually is based on indirect methods that rely on oxidation reactions that turn on/off fluorescent probes. Such methods can suffer from reaction incompleteness and interfering chemical species. We describe optimization of NMR detection that enables direct quantification of H2O2 down to the nanomolar range. Taking advantage of fast hydrogen exchange (HX) between H2O2 and water permits the use of very short interscan delays, greatly increasing sensitivity. The specific acid-, base- and water-catalyzed HX rates at 2 °C were measured to be 2.1 × 107, 6.1 × 109, and 1.4 × 10-1 M-1s-1, respectively, which result in a minimum HX rate at pH 6.2. Furthermore, the exchange is accelerated by general acid/base catalysis. MES and phosphate buffers catalyze HX strongest in their unprotonated forms. For imidazole, only the unprotonated form catalyzes HX, which contrasts with acetic acid where only the protonated state catalyzes exchange. Inorganic salts such as sodium chloride and azide have negligible effect on HX. We present optimal conditions for accurate measurement of H2O2 concentrations as low as 40 nM in aqueous samples in a few hours.
Collapse
Affiliation(s)
- Tayeb Kakeshpour
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| |
Collapse
|
14
|
Pustovalova Y, Delaglio F, Craft D, Arthanari H, Bax A, Billeter M, Bostock M, Dashti H, Hansen D, Hyberts S, Johnson B, Kazimierczuk K, Lu H, Maciejewski M, Miljenović T, Mobli M, Nietlispach D, Orekhov V, Powers R, Qu X, Robson S, Rovnyak D, Wagner G, Ying J, Zambrello M, Hoch J, Donoho D, Schuyler A. NUScon: a community-driven platform for quantitative evaluation of nonuniform sampling in NMR. Magn Reson (Gott) 2021; 2:843-861. [PMID: 37905225 PMCID: PMC10583271 DOI: 10.5194/mr-2-843-2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 11/10/2021] [Indexed: 11/02/2023]
Abstract
Although the concepts of nonuniform sampling (NUS) and non-Fourier spectral reconstruction in multidimensional NMR began to emerge 4 decades ago , it is only relatively recently that NUS has become more commonplace. Advantages of NUS include the ability to tailor experiments to reduce data collection time and to improve spectral quality, whether through detection of closely spaced peaks (i.e., "resolution") or peaks of weak intensity (i.e., "sensitivity"). Wider adoption of these methods is the result of improvements in computational performance, a growing abundance and flexibility of software, support from NMR spectrometer vendors, and the increased data sampling demands imposed by higher magnetic fields. However, the identification of best practices still remains a significant and unmet challenge. Unlike the discrete Fourier transform, non-Fourier methods used to reconstruct spectra from NUS data are nonlinear, depend on the complexity and nature of the signals, and lack quantitative or formal theory describing their performance. Seemingly subtle algorithmic differences may lead to significant variabilities in spectral qualities and artifacts. A community-based critical assessment of NUS challenge problems has been initiated, called the "Nonuniform Sampling Contest" (NUScon), with the objective of determining best practices for processing and analyzing NUS experiments. We address this objective by constructing challenges from NMR experiments that we inject with synthetic signals, and we process these challenges using workflows submitted by the community. In the initial rounds of NUScon our aim is to establish objective criteria for evaluating the quality of spectral reconstructions. We present here a software package for performing the quantitative analyses, and we present the results from the first two rounds of NUScon. We discuss the challenges that remain and present a roadmap for continued community-driven development with the ultimate aim of providing best practices in this rapidly evolving field. The NUScon software package and all data from evaluating the challenge problems are hosted on the NMRbox platform.
Collapse
Affiliation(s)
- Yulia Pustovalova
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030, USA
| | - Frank Delaglio
- Institute for Bioscience and Biotechnology Research, National Institute of Standards and Technology and the University of Maryland, Rockville, MD 20850, USA
| | - D. Levi Craft
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030, USA
| | - Haribabu Arthanari
- Department of Cancer Biology, Dana Farber Cancer Institute, Boston, MA 02215, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Ad Bax
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Martin Billeter
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 465, Gothenburg 405 30, Sweden
| | - Mark J. Bostock
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - Hesam Dashti
- Division of Preventive Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02215, USA
| | - D. Flemming Hansen
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, UK
| | - Sven G. Hyberts
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Bruce A. Johnson
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY 10031, USA
| | | | - Hengfa Lu
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen 361005, China
| | - Mark Maciejewski
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030, USA
| | - Tomas M. Miljenović
- Centre for Advanced Imaging, The University of Queensland, 4072 St Lucia, Queensland, Australia
| | - Mehdi Mobli
- Centre for Advanced Imaging, The University of Queensland, 4072 St Lucia, Queensland, Australia
| | - Daniel Nietlispach
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - Vladislav Orekhov
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 465, Gothenburg 405 30, Sweden
| | - Robert Powers
- Department of Chemistry and Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA
| | - Xiaobo Qu
- Department of Electronic Science, Biomedical Intelligent Cloud R&D Center, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, National Institute for Data Science in Health and Medicine, Xiamen University, Xiamen 361005, China
| | - Scott Anthony Robson
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - David Rovnyak
- Department of Chemistry, Bucknell University, Lewisburg, PA 17837, USA
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Jinfa Ying
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Matthew Zambrello
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030, USA
| | - Jeffrey C. Hoch
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030, USA
| | - David L. Donoho
- Department of Statistics, Stanford University, Stanford, CA 94305, USA
| | - Adam D. Schuyler
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030, USA
| |
Collapse
|
15
|
Robertson AJ, Courtney JM, Shen Y, Ying J, Bax A. Concordance of X-ray and AlphaFold2 Models of SARS-CoV-2 Main Protease with Residual Dipolar Couplings Measured in Solution. J Am Chem Soc 2021; 143:19306-19310. [PMID: 34757725 PMCID: PMC8592127 DOI: 10.1021/jacs.1c10588] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
![]()
The
68-kDa homodimeric 3C-like protease of SARS-CoV-2, Mpro (3CLpro/Nsp5), is a promising antiviral drug target. We evaluate
the concordance of models generated by the newly introduced AlphaFold2
structure prediction program with residual dipolar couplings (RDCs)
measured in solution for 15N–1HN and 13C′–1HN atom
pairs. The latter were measured using a new, highly precise TROSY-AntiTROSY
Encoded RDC (TATER) experiment. Three sets of AlphaFold2 models were
evaluated: (1) MproAF, generated using the standard
AlphaFold2 input structural database; (2) MproAFD, where the AlphaFold2 implementation was modified to exclude all
candidate template X-ray structures deposited after Jan 1, 2020; and
(3) MproAFS, which excluded all structures homologous
to coronaviral Mpro. Close agreement between all three
sets of AlphaFold models and experimental RDC data is found for most
of the protein. For residues in well-defined secondary structure,
the agreement decreases somewhat upon Amber relaxation. For these
regions, MproAF agreement exceeds that of most
high-resolution X-ray structures. Residues from domain 2 that comprise
elements of both the active site and the homo-dimerization interface
fit less well across all structures. These results indicate novel
opportunities for combining experimentation with molecular dynamics
simulations, where solution RDCs provide highly precise input for
QM/MM simulations of substrate binding/reaction trajectories.
Collapse
Affiliation(s)
- Angus J Robertson
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
| | - Joseph M Courtney
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
| | - Yang Shen
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
| | - Jinfa Ying
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
| | - Ad Bax
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
| |
Collapse
|
16
|
Abstract
The measurement and application of residual dipolar couplings (RDCs) in solution NMR studies of biological macromolecules has become well established over the past quarter of a century. Numerous methods for generating the requisite anisotropic orientational molecular distribution have been demonstrated, each with its specific strengths and weaknesses. In parallel, an enormous number of pulse schemes have been introduced to measure the many different types of RDCs, ranging from the most widely measured backbone amide 15N-1H RDCs, to 1H-1H RDCs and couplings between low-γ nuclei. Applications of RDCs range from structure validation and refinement to the determination of relative domain orientations, the measurement of backbone and domain motions, and de novo structure determination. Nevertheless, it appears that the power of the RDC methodology remains underutilized. This review aims to highlight the practical aspects of sample preparation and RDC measurement while describing some of the most straightforward applications that take advantage of the exceptionally precise information contained in such data. Some emphasis will be placed on more recent developments that enable the accurate measurement of RDCs in larger systems, which is key to the ongoing shift in focus of biological NMR spectroscopy from structure determination toward gaining improved understanding of how molecular flexibility drives protein function.
Collapse
Affiliation(s)
- Sai Chaitanya Chiliveri
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Angus J Robertson
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Yang Shen
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Dennis A Torchia
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| |
Collapse
|
17
|
Abstract
The SARS-CoV-2 virus is highly contagious, as demonstrated by numerous well-documented superspreading events. The infection commonly starts in the upper respiratory tract (URT) but can migrate to the lower respiratory tract (LRT) and other organs, often with severe consequences. Whereas LRT infection can lead to shedding of virus via breath and cough droplets, URT infection enables shedding via abundant speech droplets. Their viral load can be high in carriers with mild or no symptoms, an observation linked to the abundance of SARS-CoV-2-susceptible cells in the oral cavity epithelium. Expelled droplets rapidly lose water through evaporation, with the smaller ones transforming into long-lived aerosol. Although the largest speech droplets can carry more virions, they are few in number, fall to the ground rapidly and therefore play a relatively minor role in transmission. Of more concern is small speech aerosol, which can descend deep into the LRT and cause severe disease. However, since their total volume is small, the amount of virus they carry is low. Nevertheless, in closed environments with inadequate ventilation, they can accumulate, which elevates the risk of direct LRT infection. Of most concern is the large fraction of speech aerosol that is intermediate-sized because it remains suspended in air for minutes and can be transported over considerable distances by convective air currents. The abundance of this speech-generated aerosol, combined with its high viral load in pre- and asymptomatic individuals, strongly implicates airborne transmission of SARS-CoV-2 through speech as the primary contributor to its rapid spread.
Collapse
Affiliation(s)
- V Stadnytskyi
- From the, Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, MD, USA
| | - P Anfinrud
- From the, Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, MD, USA
| | - A Bax
- From the, Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
18
|
Chiliveri SC, Louis JM, Ghirlando R, Bax A. Transient lipid-bound states of spike protein heptad repeats provide insights into SARS-CoV-2 membrane fusion. Sci Adv 2021; 7:eabk2226. [PMID: 34623907 PMCID: PMC8500521 DOI: 10.1126/sciadv.abk2226] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Entry of SARS-CoV-2 into a host cell is mediated by spike, a class I viral fusion protein responsible for merging the viral and host cell membranes. Recent studies have revealed atomic-resolution models for both the postfusion 6-helix bundle (6HB) and the prefusion state of spike. However, a mechanistic understanding of the molecular basis for the intervening structural transition, important for the design of fusion inhibitors, has remained elusive. Using nuclear magnetic resonance spectroscopy and other biophysical methods, we demonstrate the presence of α-helical, membrane-bound, intermediate states of spike’s heptad repeat (HR1 and HR2) domains that are embedded at the lipid-water interface while in a slow dynamic equilibrium with the postfusion 6HB state. These results support a model where the HR domains lower the large energy barrier associated with membrane fusion by destabilizing the host and viral membranes, while 6HB formation actively drives their fusion by forcing physical proximity.
Collapse
Affiliation(s)
- Sai Chaitanya Chiliveri
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
- Corresponding author. (S.C.C.); (A.B.)
| | - John M. Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Rodolfo Ghirlando
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
- Corresponding author. (S.C.C.); (A.B.)
| |
Collapse
|
19
|
Robertson A, Ying J, Bax A. Four-dimensional NOE-NOE spectroscopy of SARS-CoV-2 Main Protease to facilitate resonance assignment and structural analysis. Magn Reson (Gott) 2021; 2:129-138. [PMID: 37904772 PMCID: PMC10539749 DOI: 10.5194/mr-2-129-2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/02/2021] [Indexed: 11/01/2023]
Abstract
Resonance assignment and structural studies of larger proteins by nuclear magnetic resonance (NMR) can be challenging when exchange broadening, multiple stable conformations, and 1 H back-exchange of the fully deuterated chain pose problems. These difficulties arise for the SARS-CoV-2 Main Protease, a homodimer of 2 × 306 residues. We demonstrate that the combination of four-dimensional (4D) TROSY-NOESY-TROSY spectroscopy and 4D NOESY-NOESY-TROSY spectroscopy provides an effective tool for delineating the 1 H-1 H dipolar relaxation network. In combination with detailed structural information obtained from prior X-ray crystallography work, such data are particularly useful for extending and validating resonance assignments as well as for probing structural features.
Collapse
Affiliation(s)
- Angus J. Robertson
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| |
Collapse
|
20
|
Courtney JM, Bax A. Hydrating the respiratory tract: An alternative explanation why masks lower severity of COVID-19. Biophys J 2021; 120:994-1000. [PMID: 33582134 PMCID: PMC7879047 DOI: 10.1016/j.bpj.2021.02.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 12/30/2022] Open
Abstract
The seasonality of respiratory diseases has been linked, among other factors, to low outdoor absolute humidity and low indoor relative humidity, which increase evaporation of water in the mucosal lining of the respiratory tract. We demonstrate that normal breathing results in an absorption-desorption cycle inside facemasks, in which supersaturated air is absorbed by the mask fibers during expiration, followed by evaporation during inspiration of dry environmental air. For double-layered cotton masks, which have considerable heat capacity, the temperature of inspired air rises above room temperature, and the effective increase in relative humidity can exceed 100%. We propose that the recently reported, disease-attenuating effect of generic facemasks is dominated by the strong humidity increase of inspired air. This elevated humidity promotes mucociliary clearance of pathogens from the lungs, both before and after an infection of the upper respiratory tract has occurred. Effective mucociliary clearance can delay and reduce infection of the lower respiratory tract, thus mitigating disease severity. This mode of action suggests that masks can benefit the wearer even after an infection in the upper respiratory tract has occurred, complementing the traditional function of masks to limit person-to-person disease transmission. This potential therapeutical use should be studied further.
Collapse
Affiliation(s)
- Joseph M Courtney
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland
| | - Ad Bax
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland.
| |
Collapse
|
21
|
Chiliveri SC, Louis JM, Bax A. Concentration‐Dependent Structural Transition of the HIV‐1 gp41 MPER Peptide into α‐Helical Trimers. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202008804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sai Chaitanya Chiliveri
- Laboratory of Chemical Physics National Institute of Diabetes and Digestive and Kidney Diseases Bethesda MD 20892 USA
| | - John M. Louis
- Laboratory of Chemical Physics National Institute of Diabetes and Digestive and Kidney Diseases Bethesda MD 20892 USA
| | - Ad Bax
- Laboratory of Chemical Physics National Institute of Diabetes and Digestive and Kidney Diseases Bethesda MD 20892 USA
| |
Collapse
|
22
|
Abstract
Seasonality of respiratory diseases has been linked, among other factors, to low outdoor absolute humidity and low relative humidity in indoor environments, which increase evaporation of water in the mucosal layer lining the respiratory tract. We demonstrate that normal breathing results in an absorption-desorption cycle inside facemasks, where super-saturated air is absorbed by the mask fibers during expiration, followed by evaporation during inspiration of dry environmental air. For double-layered cotton masks, which have considerable heat capacity, the temperature of inspired air rises above room temperature, and the effective increase in relative humidity can exceed 100%. We propose that the recently reported, disease-attenuating effect of generic facemasks is dominated by the strong humidity increase of inspired air. SIGNIFICANCE STATEMENT Facemasks are the most widely used tool for mitigating the spread of the COVID-19 pandemic. Decreased disease severity by the wearer has also been linked to the use of cloth facemasks. This well-documented finding is surprising considering that such masks are poor at filtering the smallest aerosol particles, which can reach the lower respiratory tract and have been associated with severe disease. We show that facemasks strongly increase the effective humidity of inhaled air, thereby promoting hydration of the respiratory epithelium which is known to be beneficial to the immune system. Increased humidity of inspired air could be an alternate explanation for the now well-established link between mask wearing and lower disease severity.
Collapse
Affiliation(s)
- Joseph M Courtney
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, MD, 20892-0520, USA
| | - Ad Bax
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, MD, 20892-0520, USA
| |
Collapse
|
23
|
Kakeshpour T, Ramanujam V, Barnes CA, Shen Y, Ying J, Bax A. A lowly populated, transient β-sheet structure in monomeric Aβ 1-42 identified by multinuclear NMR of chemical denaturation. Biophys Chem 2020; 270:106531. [PMID: 33453683 DOI: 10.1016/j.bpc.2020.106531] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/08/2020] [Accepted: 12/13/2020] [Indexed: 02/07/2023]
Abstract
Chemical denaturation is a well-established approach for probing the equilibrium between folded and unfolded states of proteins. We demonstrate applicability of this method to the detection of a small population of a transiently folded structural element in a system that is often considered to be intrinsically fully disordered. The 1HN, 15N, 13Cα, and 13C' chemical shifts of Aβ1-40 and Aβ1-42 peptides and their M35-oxidized variants were monitored as a function of urea concentration and compared to analogous urea titrations of synthetic pentapeptides of homologous sequence. Fitting of the chemical shift titrations yields a 10 ± 1% population for a structured element at the C-terminus of Aβ1-42 that folds with a cooperativity of m = 0.06 kcal/mol·M. The fit also yields the chemical shifts of the folded state and, using a database search, for Aβ1-42 these shifts identified an antiparallel intramolecular β-sheet for residues I32-A42, linked by a type I' β-turn at G37 and G38. The structure is destabilized by oxidation of M35. Paramagnetic relaxation rates and two previously reported weak, medium-range NOE interactions are consistent with this transient β-sheet. Introduction of the requisite A42C mutation and tagging with MTSL resulted in a small stabilization of this β-sheet. Chemical shift analysis suggests a C-terminal β-sheet may be present in Aβ1-40 too, but the turn type at G37 is not type I'. The approach to derive Transient Structure from chemical Denaturation by NMR (TSD-NMR), demonstrated here for Aβ peptides, provides a sensitive tool for identifying the presence of lowly populated, transiently ordered elements in proteins that are considered to be intrinsically disordered, and permits extraction of structural data for such elements.
Collapse
Affiliation(s)
- Tayeb Kakeshpour
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Venkat Ramanujam
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - C Ashley Barnes
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Yang Shen
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA.
| |
Collapse
|
24
|
Chiliveri SC, Louis JM, Bax A. Concentration-Dependent Structural Transition of the HIV-1 gp41 MPER Peptide into α-Helical Trimers. Angew Chem Int Ed Engl 2020; 60:166-170. [PMID: 32916024 DOI: 10.1002/anie.202008804] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/20/2020] [Indexed: 11/12/2022]
Abstract
The membrane proximal external region (MPER) of HIV-1 gp41 contains epitopes for at least four broadly neutralizing antibodies. Depending on solution conditions and construct design, different structures have been reported for this segment. We show that in aqueous solution the MPER fragment (gp160660-674 ) exists in a monomer-trimer equilibrium with an association constant in the micromolar range. Thermodynamic analysis reveals that the association is exothermic, more favorable in D2 O than H2 O, and increases with ionic strength, indicating hydrophobically driven intermolecular interactions. Circular dichroism, 13 Cα chemical shifts, NOE, and hydrogen exchange rates reveal that MPER undergoes a structural transition from predominately unfolded monomer at low concentrations to an α-helical trimer at high concentrations. This result has implications for antibody recognition of MPER prior to and during the process where gp41 switches from a pre-hairpin intermediate to its post-fusion 6-helical bundle state.
Collapse
Affiliation(s)
- Sai Chaitanya Chiliveri
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 20892, USA
| | - John M Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 20892, USA
| |
Collapse
|
25
|
Alderson TR, Ying J, Bax A, Benesch JLP, Baldwin AJ. Conditional Disorder in Small Heat-shock Proteins. J Mol Biol 2020; 432:3033-3049. [PMID: 32081587 PMCID: PMC7245567 DOI: 10.1016/j.jmb.2020.02.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/27/2020] [Accepted: 02/09/2020] [Indexed: 12/31/2022]
Abstract
Small heat-shock proteins (sHSPs) are molecular chaperones that respond to cellular stresses to combat protein aggregation. HSP27 is a critical human sHSP that forms large, dynamic oligomers whose quaternary structures and chaperone activities depend on environmental factors. Upon exposure to cellular stresses, such as heat shock or acidosis, HSP27 oligomers can dissociate into dimers and monomers, which leads to significantly enhanced chaperone activity. The structured core of the protein, the α-crystallin domain (ACD), forms dimers and can prevent the aggregation of substrate proteins to a similar degree as the full-length protein. When the ACD dimer dissociates into monomers, it partially unfolds and exhibits enhanced activity. Here, we used solution-state NMR spectroscopy to characterize the structure and dynamics of the HSP27 ACD monomer. Web show that the monomer is stabilized at low pH and that its backbone chemical shifts, 15N relaxation rates, and 1H-15N residual dipolar couplings suggest structural changes and rapid motions in the region responsible for dimerization. By analyzing the solvent accessible and buried surface areas of sHSP structures in the context of a database of dimers that are known to dissociate into disordered monomers, we predict that ACD dimers from sHSPs across all kingdoms of life may partially unfold upon dissociation. We propose a general model in which conditional disorder-the partial unfolding of ACDs upon monomerization-is a common mechanism for sHSP activity.
Collapse
Affiliation(s)
- T Reid Alderson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK; Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Justin L P Benesch
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK.
| | - Andrew J Baldwin
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK.
| |
Collapse
|
26
|
Barnes CA, Shen Y, Ying J, Bax A. Modulating the Stiffness of the Myosin VI Single α-Helical Domain. Biophys J 2020; 118:1119-1128. [PMID: 32049057 DOI: 10.1016/j.bpj.2020.01.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/20/2019] [Accepted: 01/02/2020] [Indexed: 11/28/2022] Open
Abstract
Highly charged, single α-helical (SAH) domains contain a high percentage of Arg, Lys, and Glu residues. Their dynamic salt bridge pairing creates the exceptional stiffness of these helical rods, with a persistence length of more than 200 Å for the myosin VI SAH domain. With the aim of modulating the stiffness of the helical structure, we investigated the effect, using NMR spectroscopy, of substituting key charged Arg, Lys, Glu, and Asp residues by Gly or His. Results indicate that such mutations result in the transient breaking of the helix at the site of mutation but with noticeable impact on amide hydrogen exchange rates extending as far as ±2 helical turns, pointing to a substantial degree of cooperativity in SAH stability. Whereas a single Gly substitution caused transient breaks ∼20% of the time, two consecutive Gly substitutions break the helix ∼65% of the time. NMR relaxation measurements indicate that the exchange rate between an intact and a broken helix is fast (>300,000 s-1) and that for the wild-type sequence, the finite persistence length is dominated by thermal fluctuations of backbone torsion angles and H-bond lengths, not by transient helix breaking. The double mutation D27H/E28H causes a pH-dependent fraction of helix disruption, in which the helix breakage increases from 26% at pH 7.5 to 53% at pH 5.5. The ability to modulate helical integrity by pH may enable incorporation of externally tunable dynamic components in the design of molecular machines.
Collapse
Affiliation(s)
- C Ashley Barnes
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland
| | - Yang Shen
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland
| | - Jinfa Ying
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland
| | - Ad Bax
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland.
| |
Collapse
|
27
|
Ramanujam V, Alderson TR, Pritišanac I, Ying J, Bax A. Protein structural changes characterized by high-pressure, pulsed field gradient diffusion NMR spectroscopy. J Magn Reson 2020; 312:106701. [PMID: 32113145 PMCID: PMC7153785 DOI: 10.1016/j.jmr.2020.106701] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 02/16/2020] [Accepted: 02/17/2020] [Indexed: 06/10/2023]
Abstract
Pulsed-field gradient NMR spectroscopy is widely used to measure the translational diffusion and hydrodynamic radius (Rh) of biomolecules in solution. For unfolded proteins, the Rh provides a sensitive reporter on the ensemble-averaged conformation and the extent of polypeptide chain expansion as a function of added denaturant. Hydrostatic pressure is a convenient and reversible alternative to chemical denaturants for the study of protein folding, and enables NMR measurements to be performed on a single sample. While the impact of pressure on the viscosity of water is well known, and our water diffusivity measurements agree closely with theoretical expectations, we find that elevated pressures increase the Rh of dioxane and other small molecules by amounts that correlate with their hydrophobicity, with parallel increases in rotational friction indicated by 13C longitudinal relaxation times. These data point to a tighter coupling with water for hydrophobic surfaces at elevated pressures. Translational diffusion measurement of the unfolded state of a pressure-sensitized ubiquitin mutant (VA2-ubiquitin) as a function of hydrostatic pressure or urea concentration shows that Rh values of both the folded and the unfolded states remain nearly invariant. At ca 23 Å, the Rh of the fully pressure-denatured state is essentially indistinguishable from the urea-denatured state, and close to the value expected for an idealized random coil of 76 residues. The intrinsically disordered protein (IDP) α-synuclein shows slight compaction at pressures above 2 kbar. Diffusion of unfolded ubiquitin and α-synuclein is significantly impacted by sample concentration, indicating that quantitative measurements need to be carried out under dilute conditions.
Collapse
Affiliation(s)
- Venkatraman Ramanujam
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, 60438 Frankfurt am Main, Germany
| | - T Reid Alderson
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, 60438 Frankfurt am Main, Germany
| | - Iva Pritišanac
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, 60438 Frankfurt am Main, Germany
| | - Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, 60438 Frankfurt am Main, Germany
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, 60438 Frankfurt am Main, Germany.
| |
Collapse
|
28
|
Ramanujam V, Charlier C, Bax A. Observation and Kinetic Characterization of Transient Schiff Base Intermediates by CEST NMR Spectroscopy. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201908416] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Venkatraman Ramanujam
- Laboratory of Chemical Physics National Institute of Diabetes and Digestive and Kidney Diseases Bethesda MD 20892 USA
| | - Cyril Charlier
- Laboratory of Chemical Physics National Institute of Diabetes and Digestive and Kidney Diseases Bethesda MD 20892 USA
| | - Ad Bax
- Laboratory of Chemical Physics National Institute of Diabetes and Digestive and Kidney Diseases Bethesda MD 20892 USA
| |
Collapse
|
29
|
Ramanujam V, Charlier C, Bax A. Observation and Kinetic Characterization of Transient Schiff Base Intermediates by CEST NMR Spectroscopy. Angew Chem Int Ed Engl 2019; 58:15309-15312. [PMID: 31449352 DOI: 10.1002/anie.201908416] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Indexed: 01/15/2023]
Abstract
In aqueous solution, many biochemical reaction pathways involve reaction of an aldehyde with an amine, which progresses through generally unstable, hydrated and dehydrated, Schiff base intermediates that often are unobservable by conventional NMR. There are 4 states in the relevant equilibrium: 1) gem-diol, 2) aldehyde, 3) hemiaminal, and 4) Schiff base. For the reaction between protein amino groups and DOPAL, a highly toxic metabolite of dopamine, the 1 H resonances of both the hemiaminal and the dehydrated Schiff base can be observed by CEST NMR, even when their populations fall below 0.1 %. CEST NMR reveals the quantitative exchange kinetics between reactants and Schiff base intermediates, explaining why the Schiff base NMR signals are rarely observed. The reactivity of DOPAL with Nα -amino groups is greater than with lysine Nϵ -amines and, in the presence of O2 , both types of Schiff base DOPAL-peptide intermediates rapidly react with free DOPAL to irreversibly form dicatechol pyrrole adducts.
Collapse
Affiliation(s)
- Venkatraman Ramanujam
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 20892, USA
| | - Cyril Charlier
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 20892, USA
| |
Collapse
|
30
|
Ying J, Barnes CA, Louis JM, Bax A. Importance of time-ordered non-uniform sampling of multi-dimensional NMR spectra of Aβ 1-42 peptide under aggregating conditions. J Biomol NMR 2019; 73:429-441. [PMID: 31407200 PMCID: PMC6819256 DOI: 10.1007/s10858-019-00235-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 02/09/2019] [Indexed: 06/02/2023]
Abstract
Although the order of the time steps in which the non-uniform sampling (NUS) schedule is implemented when acquiring multi-dimensional NMR spectra is of limited importance when sample conditions remain unchanged over the course of the experiment, it is shown to have major impact when samples are unstable. In the latter case, time-ordering of the NUS data points by the normalized radial length yields a reduction of sampling artifacts, regardless of the spectral reconstruction algorithm. The disadvantage of time-ordered NUS sampling is that halting the experiment prior to its completion will result in lower spectral resolution, rather than a sparser data matrix. Alternatively, digitally correcting for sample decay prior to reconstruction of randomly ordered NUS data points can mitigate reconstruction artifacts, at the cost of somewhat lower sensitivity. Application of these sampling schemes to the Alzheimer's amyloid beta (Aβ1-42) peptide at an elevated concentration, low temperature, and 3 kbar of pressure, where approximately 75% of the peptide reverts to an NMR-invisible state during the collection of a 3D 15N-separated NOESY spectrum, highlights the improvement in artifact suppression and reveals weak medium-range NOE contacts in several regions, including the C-terminal region of the peptide.
Collapse
Affiliation(s)
- Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - C Ashley Barnes
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - John M Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
| |
Collapse
|
31
|
Abstract
Over the past approximately three decades, isotope-directed NMR spectroscopy has become a powerful method for determining 3D structures of biological macromolecules and their complexes in solution. From a structural perspective NMR provides an invaluable tool for studying systems that are not amenable to crystallization, including intrinsically disordered proteins and weak complexes. In contrast to both X-ray crystallography and cryo-electron microscopy which afford a largely static view of the systems under consideration, the great power of NMR lies in its ability to quantitatively probe exchange dynamics between interconverting states, and to reveal and characterize at atomic resolution the existence of transient states that may be populated at levels as low as 1%. Such "excited" states play a key role in macromolecular recognition, allostery, signal transduction and macromolecular assembly, including the initial events involved in aggregation and amyloid formation. Optimal application of NMR to such systems of fundamental biological interest requires a sound footing of the physical underpinnings of today's and tomorrow's sophisticated NMR experiments.
Collapse
Affiliation(s)
- Ad Bax
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, MD 20892-0520, USA.
| | - G Marius Clore
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, MD 20892-0520, USA.
| |
Collapse
|
32
|
Barnes CA, Robertson AJ, Louis JM, Anfinrud P, Bax A. Observation of β-Amyloid Peptide Oligomerization by Pressure-Jump NMR Spectroscopy. J Am Chem Soc 2019; 141:13762-13766. [DOI: 10.1021/jacs.9b06970] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- C. Ashley Barnes
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Angus J. Robertson
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - John M. Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Philip Anfinrud
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| |
Collapse
|
33
|
Barnes CA, Shen Y, Ying J, Takagi Y, Torchia DA, Sellers JR, Bax A. Remarkable Rigidity of the Single α-Helical Domain of Myosin-VI As Revealed by NMR Spectroscopy. J Am Chem Soc 2019; 141:9004-9017. [PMID: 31117653 PMCID: PMC6556874 DOI: 10.1021/jacs.9b03116] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Indexed: 11/29/2022]
Abstract
Although the α-helix has long been recognized as an all-important element of secondary structure, it generally requires stabilization by tertiary interactions with other parts of a protein's structure. Highly charged single α-helical (SAH) domains, consisting of a high percentage (>75%) of Arg, Lys, and Glu residues, are exceptions to this rule but have been difficult to characterize structurally. Our study focuses on the 68-residue medial tail domain of myosin-VI, which is found to contain a highly ordered α-helical structure extending from Glu-6 to Lys-63. High hydrogen exchange protection factors (15-150), small (ca. 4 Hz) 3 JHNHα couplings, and a near-perfect fit to an ideal model α-helix for its residual dipolar couplings (RDCs), measured in a filamentous phage medium, support the high regularity of this helix. Remarkably, the hydrogen exchange rates are far more homogeneous than the protection factors derived from them, suggesting that for these transiently broken helices the intrinsic exchange rates derived from the amino acid sequence are not appropriate reference values. 15N relaxation data indicate a very high degree of rotational diffusion anisotropy ( D∥/ D⊥ ≈ 7.6), consistent with the hydrodynamic behavior predicted for such a long, nearly straight α-helix. Alignment of the helix by a paramagnetic lanthanide ion attached to its N-terminal region shows a decrease in alignment as the distance from the tagging site increases. This decrease yields a precise measure for the persistence length of 224 ± 10 Å at 20 °C, supporting the idea that the role of the SAH helix is to act as an extension of the myosin-VI lever arm.
Collapse
|
34
|
Courtney JM, Charlier C, Bax A. Structural Characterization of a Ubiquitin Folding Intermediate by Pressure-Jump NMR. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.1841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
|
35
|
Wuliji T, Bax A, Wuri L, Wilbers L, Boeckmann C. PSVI-34 Producing organic fall lamb using an out-of-season breeding scheme for hair sheep. J Anim Sci 2018. [DOI: 10.1093/jas/sky404.1015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- T Wuliji
- Lincoln University of Missouri,Holts Summit, MO, United States
| | - A Bax
- Lincoln University of Missouri,Jefferson City, MO, United States
| | - L Wuri
- Lincoln University of Missouri,Jefferson City, MO, United States
| | - L Wilbers
- Lincoln University of Missouri,Jefferson City, MO, United States
| | - C Boeckmann
- Lincoln University of Missouri,Jefferson City, MO, United States
| |
Collapse
|
36
|
Charlier C, Courtney JM, Anfinrud P, Bax A. Interrupted Pressure-Jump NMR Experiments Reveal Resonances of On-Pathway Protein Folding Intermediate. J Phys Chem B 2018; 122:11792-11799. [PMID: 30256104 DOI: 10.1021/acs.jpcb.8b08456] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Previous pressure-jump NMR experiments on a pressure-sensitized double mutant of ubiquitin showed evidence that its folding occurs via two parallel, comparably efficient pathways: a single barrier and a two-barrier pathway. An interrupted folding NMR experiment is introduced, where for a brief period the pressure is dropped to atmospheric conditions (1 bar), followed by a jump back to high pressure for signal detection. Conventional, forward sampling of the indirect dimension during the low-pressure period correlates the 15N or 13C' chemical shifts of the unfolded protein at 1 bar to the 1H frequencies of both the unfolded and folded proteins at high pressure. Remarkably, sampling the data of the same experiment in the reverse direction yields the frequencies of proteins present at the end of the low-pressure interval, which include unfolded, intermediate, and folded species. Although the folding intermediate 15N shifts differ strongly from natively folded protein, its 13C' chemical shifts, which are more sensitive probes for secondary structure, closely match those of the folded protein and indicate that the folding intermediate must have a structure that is quite similar to the native state.
Collapse
Affiliation(s)
- Cyril Charlier
- Laboratory of Chemical Physics, NIDDK , National Institutes of Health , Bethesda , Maryland 20892-0520 , United States
| | - Joseph M Courtney
- Laboratory of Chemical Physics, NIDDK , National Institutes of Health , Bethesda , Maryland 20892-0520 , United States
| | - Philip Anfinrud
- Laboratory of Chemical Physics, NIDDK , National Institutes of Health , Bethesda , Maryland 20892-0520 , United States
| | - Ad Bax
- Laboratory of Chemical Physics, NIDDK , National Institutes of Health , Bethesda , Maryland 20892-0520 , United States
| |
Collapse
|
37
|
Natarajan K, Jiang J, May NA, Mage MG, Boyd LF, McShan AC, Sgourakis NG, Bax A, Margulies DH. The Role of Molecular Flexibility in Antigen Presentation and T Cell Receptor-Mediated Signaling. Front Immunol 2018; 9:1657. [PMID: 30065727 PMCID: PMC6056622 DOI: 10.3389/fimmu.2018.01657] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 07/04/2018] [Indexed: 01/20/2023] Open
Abstract
Antigen presentation is a cellular process that involves a number of steps, beginning with the production of peptides by proteolysis or aberrant synthesis and the delivery of peptides to cellular compartments where they are loaded on MHC class I (MHC-I) or MHC class II (MHC-II) molecules. The selective loading and editing of high-affinity immunodominant antigens is orchestrated by molecular chaperones: tapasin/TAP-binding protein, related for MHC-I and HLA-DM for MHC-II. Once peptide/MHC (pMHC) complexes are assembled, following various steps of quality control, they are delivered to the cell surface, where they are available for identification by αβ receptors on CD8+ or CD4+ T lymphocytes. In addition, recognition of cell surface peptide/MHC-I complexes by natural killer cell receptors plays a regulatory role in some aspects of the innate immune response. Many of the components of the pathways of antigen processing and presentation and of T cell receptor (TCR)-mediated signaling have been studied extensively by biochemical, genetic, immunological, and structural approaches over the past several decades. Until recently, however, dynamic aspects of the interactions of peptide with MHC, MHC with molecular chaperones, or of pMHC with TCR have been difficult to address experimentally, although computational approaches such as molecular dynamics (MD) simulations have been illuminating. Studies exploiting X-ray crystallography, cryo-electron microscopy, and multidimensional nuclear magnetic resonance (NMR) spectroscopy are beginning to reveal the importance of molecular flexibility as it pertains to peptide loading onto MHC molecules, the interactions between pMHC and TCR, and subsequent TCR-mediated signals. In addition, recent structural and dynamic insights into how molecular chaperones define peptide selection and fine-tune the MHC displayed antigen repertoire are discussed. Here, we offer a review of current knowledge that highlights experimental data obtained by X-ray crystallography and multidimensional NMR methodologies. Collectively, these findings strongly support a multifaceted role for protein plasticity and conformational dynamics throughout the antigen processing and presentation pathway in dictating antigen selection and recognition.
Collapse
Affiliation(s)
- Kannan Natarajan
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Jiansheng Jiang
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Nathan A May
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Michael G Mage
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Lisa F Boyd
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Andrew C McShan
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, CA, United States
| | - Nikolaos G Sgourakis
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, CA, United States
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - David H Margulies
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| |
Collapse
|
38
|
Charlier C, Courtney JM, Alderson TR, Anfinrud P, Bax A. Monitoring 15N Chemical Shifts During Protein Folding by Pressure-Jump NMR. J Am Chem Soc 2018; 140:8096-8099. [PMID: 29923716 DOI: 10.1021/jacs.8b04833] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pressure-jump hardware permits direct observation of protein NMR spectra during a cyclically repeated protein folding process. For a two-state folding protein, the change in resonance frequency will occur nearly instantaneously when the protein clears the transition state barrier, resulting in a monoexponential change of the ensemble-averaged chemical shift. However, protein folding pathways can be more complex and contain metastable intermediates. With a pseudo-3D NMR experiment that utilizes stroboscopic observation, we measure the ensemble-averaged chemical shifts, including those of exchange-broadened intermediates, during the folding process. Such measurements for a pressure-sensitized mutant of ubiquitin show an on-pathway kinetic intermediate whose 15N chemical shifts differ most from the natively folded protein for strands β5, its preceding turn, and the two strands that pair with β5 in the native structure.
Collapse
Affiliation(s)
- Cyril Charlier
- Laboratory of Chemical Physics, NIDDK , National Institutes of Health , Bethesda , Maryland 20892-0520 , United States
| | - Joseph M Courtney
- Laboratory of Chemical Physics, NIDDK , National Institutes of Health , Bethesda , Maryland 20892-0520 , United States
| | - T Reid Alderson
- Laboratory of Chemical Physics, NIDDK , National Institutes of Health , Bethesda , Maryland 20892-0520 , United States
| | - Philip Anfinrud
- Laboratory of Chemical Physics, NIDDK , National Institutes of Health , Bethesda , Maryland 20892-0520 , United States
| | - Ad Bax
- Laboratory of Chemical Physics, NIDDK , National Institutes of Health , Bethesda , Maryland 20892-0520 , United States
| |
Collapse
|
39
|
Marchant J, Bax A, Summers MF. Accurate Measurement of Residual Dipolar Couplings in Large RNAs by Variable Flip Angle NMR. J Am Chem Soc 2018; 140:6978-6983. [PMID: 29757635 DOI: 10.1021/jacs.8b03298] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
NMR approaches using nucleotide-specific deuterium labeling schemes have enabled structural studies of biologically relevant RNAs of increasing size and complexity. Although local structure is well-determined using these methods, definition of global structural features, including relative orientations of independent helices, remains a challenge. Residual dipolar couplings, a potential source of orientation information, have not been obtainable for large RNAs due to poor sensitivity resulting from rapid heteronuclear signal decay. Here we report a novel multiple quantum NMR method for RDC determination that employs flip angle variation rather than a coupling evolution period. The accuracy of the method and its utility for establishing interhelical orientations are demonstrated for a 36-nucleotide RNA, for which comparative data could be obtained. Applied to a 78 kDa Rev response element from the HIV-1 virus, which has an effective rotational correlation time of ca. 160 ns, the method yields sensitivity gains of an order of magnitude or greater over existing approaches. Solution-state access to structural organization in RNAs of at least 230 nucleotides is now possible.
Collapse
Affiliation(s)
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes, Digestive and Kidney Diseases , National Institutes of Health , Bethesda , Maryland 20892 , United States
| | | |
Collapse
|
40
|
Abstract
3,4-Dihydroxyphenylacetaldehyde (DOPAL) is a toxic and reactive product of dopamine catabolism. In the catecholaldehyde hypothesis for Parkinson's disease, it is a critical driver of the selective loss of dopaminergic neurons that characterizes the disease. DOPAL also cross-links α-synuclein, the main component of Lewy bodies, which are a pathological hallmark of the disease. We previously described the initial adduct formed in reactions between DOPAL and α-synuclein, a dicatechol pyrrole lysine (DCPL). Here, we examine the chemical basis for DOPAL-based cross-linking. We find that autoxidation of DCPL's catechol rings spurs its decomposition, yielding an intermediate dicatechol isoindole lysine (DCIL) product formed by an intramolecular reaction of the two catechol rings to give an unstable tetracyclic structure. DCIL then reacts with a second DCIL to give a dimeric, di-DCIL. This product is formed by an intermolecular carbon-carbon bond between the isoindole rings of the two DCILs that generates two structurally nonequivalent and separable atropisomers. Using α-synuclein, we demonstrate that the DOPAL-catalyzed formation of oligomers can be separated into two steps. The initial adduct formation occurs robustly within an hour, with DCPL as the main product, and the second step cross-links α-synuclein molecules. Exploiting this two-stage reaction, we use an isotopic labeling approach to show the predominant cross-linking mechanism is an interadduct reaction. Finally, we confirm that a mass consistent with a di-DCIL linkage can be observed in dimeric α-synuclein by mass spectrometry. Our work elucidates previously unknown pathways of catechol-based oxidative protein damage and will facilitate efforts to detect DOPAL-based cross-links in disease-state neurons.
Collapse
Affiliation(s)
- Jonathan W. Werner-Allen
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, United States
| | - Sarah Monti
- Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Jenna F. DuMond
- Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Rodney L. Levine
- Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, United States
| |
Collapse
|
41
|
Chiliveri SC, Louis JM, Ghirlando R, Baber JL, Bax A. Tilted, Uninterrupted, Monomeric HIV-1 gp41 Transmembrane Helix from Residual Dipolar Couplings. J Am Chem Soc 2017; 140:34-37. [PMID: 29277995 DOI: 10.1021/jacs.7b10245] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Cryo-electron microscopy and X-ray crystallography have shown that the pre- and postfusion states of the HIV-1 gp41 viral coat protein, although very different from one another, each adopt C3 symmetric structures. A stable homotrimeric structure for the transmembrane domain (TM) also was modeled and supported by experimental data. For a C3 symmetric structure, alignment in an anisotropic medium must be axially symmetric, with the unique axis of the alignment tensor coinciding with the C3 axis. However, NMR residual dipolar couplings (RDCs) measured under three different alignment conditions were found to be incompatible with C3 symmetry. Subsequent measurements by paramagnetic relaxation enhancement, analytical ultracentrifugation, and DEER EPR, indicate that the transmembrane domain is monomeric. 15N NMR relaxation data and RDCs show that TM is highly ordered and uninterrupted for a total length of 32 residues, extending well into the membrane proximal external region.
Collapse
Affiliation(s)
- Sai Chaitanya Chiliveri
- Laboratory of Chemical Physics and ‡Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - John M Louis
- Laboratory of Chemical Physics and ‡Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - Rodolfo Ghirlando
- Laboratory of Chemical Physics and ‡Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - James L Baber
- Laboratory of Chemical Physics and ‡Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - Ad Bax
- Laboratory of Chemical Physics and ‡Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
| |
Collapse
|
42
|
Abstract
In unfolded proteins, peptide bonds involving Pro residues exist in equilibrium between the minor cis and major trans conformations. Folded proteins predominantly contain trans-Pro bonds, and slow cis-trans Pro isomerization in the unfolded state is often found to be a rate-limiting step in protein folding. Moreover, kinases and phosphatases that act upon Ser/Thr-Pro motifs exhibit preferential recognition of either the cis- or trans-Pro conformer. Here, NMR spectra obtained at both atmospheric and high pressures indicate that the population of cis-Pro falls well below previous estimates, an effect attributed to the use of short peptides with charged termini in most prior model studies. For the intrinsically disordered protein α-synuclein, cis-Pro populations at all of its five X-Pro bonds are less than 5 %, with only modest ionic strength dependence and no detectable effect of the previously demonstrated interaction between the N- and C-terminal halves of the protein. Comparison to small peptides with the same amino-acid sequence indicates that peptides, particularly those with unblocked, oppositely charged amino and carboxyl end groups, strongly overestimate the amount of cis-Pro.
Collapse
Affiliation(s)
- T Reid Alderson
- Laboratory of Chemical Physics, National Institutes of Health, 5 Memorial Drive, Bethesda, MD, 20892, USA
| | - Jung Ho Lee
- Laboratory of Chemical Physics, National Institutes of Health, 5 Memorial Drive, Bethesda, MD, 20892, USA
| | - Cyril Charlier
- Laboratory of Chemical Physics, National Institutes of Health, 5 Memorial Drive, Bethesda, MD, 20892, USA
| | - Jinfa Ying
- Laboratory of Chemical Physics, National Institutes of Health, 5 Memorial Drive, Bethesda, MD, 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institutes of Health, 5 Memorial Drive, Bethesda, MD, 20892, USA
| |
Collapse
|
43
|
Shen Y, Roche J, Grishaev A, Bax A. Prediction of nearest neighbor effects on backbone torsion angles and NMR scalar coupling constants in disordered proteins. Protein Sci 2017; 27:146-158. [PMID: 28884933 DOI: 10.1002/pro.3292] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 09/03/2017] [Accepted: 09/05/2017] [Indexed: 12/29/2022]
Abstract
Using fine-tuned hydrogen bonding criteria, a library of coiled peptide fragments has been generated from a large set of high-resolution protein X-ray structures. This library is shown to be an improved representation of ϕ/ψ torsion angles seen in intrinsically disordered proteins (IDPs). The ϕ/ψ torsion angle distribution of the library, on average, provides good agreement with experimentally observed chemical shifts and 3 JHN-Hα coupling constants for a set of five disordered proteins. Inspection of the coil library confirms that nearest-neighbor effects significantly impact the ϕ/ψ distribution of residues in the coil state. Importantly, 3 JHN-Hα coupling constants derived from the nearest-neighbor modulated backbone ϕ distribution in the coil library show improved agreement to experimental values, thereby providing a better way to predict 3 JHN-Hα coupling constants for IDPs, and for identifying locations that deviate from fully random behavior.
Collapse
Affiliation(s)
- Yang Shen
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, 20892-0520
| | - Julien Roche
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, 20892-0520
| | - Alexander Grishaev
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, 20892-0520.,National Institute of Standards and Technology and the Institute for Bioscience and Biotechnology Research, Rockville, Maryland, 20850
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, 20892-0520
| |
Collapse
|
44
|
Alderson TR, Charlier C, Torchia DA, Anfinrud P, Bax A. Monitoring Hydrogen Exchange During Protein Folding by Fast Pressure Jump NMR Spectroscopy. J Am Chem Soc 2017; 139:11036-11039. [PMID: 28766333 DOI: 10.1021/jacs.7b06676] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A method is introduced that permits direct observation of the rates at which backbone amide hydrogens become protected from solvent exchange after rapidly dropping the hydrostatic pressure inside the NMR sample cell from denaturing (2.5 kbar) to native (1 bar) conditions. The method is demonstrated for a pressure-sensitized ubiquitin variant that contains two Val to Ala mutations. Increased protection against hydrogen exchange with solvent is monitored as a function of time during the folding process. Results for 53 backbone amides show narrow clustering with protection occurring with a time constant of ca. 85 ms, but slower protection is observed around a reverse turn near the C-terminus of the protein. Remarkably, the native NMR spectrum returns with this slower time constant of ca. 150 ms, indicating that the almost fully folded protein retains molten globule characteristics with severe NMR line broadening until the final hydrogen bonds are formed. Prior to crossing the transition state barrier, hydrogen exchange protection factors are close to unity, but with slightly elevated values in the β1-β2 hairpin, previously shown to be already lowly populated in the urea-denatured state.
Collapse
Affiliation(s)
- T Reid Alderson
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health , Bethesda, Maryland 20892-0520, United States
| | - Cyril Charlier
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health , Bethesda, Maryland 20892-0520, United States
| | - Dennis A Torchia
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health , Bethesda, Maryland 20892-0520, United States
| | - Philip Anfinrud
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health , Bethesda, Maryland 20892-0520, United States
| | - Ad Bax
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health , Bethesda, Maryland 20892-0520, United States
| |
Collapse
|
45
|
Stolzenberg E, Berry D, Yang D, Lee EY, Kroemer A, Kaufman S, Wong GCL, Oppenheim JJ, Sen S, Fishbein T, Bax A, Harris B, Barbut D, Zasloff MA. A Role for Neuronal Alpha-Synuclein in Gastrointestinal Immunity. J Innate Immun 2017. [PMID: 28651250 DOI: 10.1159/000477990] [Citation(s) in RCA: 187] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Alpha-synuclein (αS) is a nerve cell protein associated with Parkinson disease (PD). Accumulation of αS within the enteric nervous system (ENS) and its traffic from the gut to the brain are implicated in the pathogenesis and progression of PD. αS has no known function in humans and the reason for its accumulation within the ENS is unknown. Several recent studies conducted in rodents have linked αS to immune cell activation in the central nervous system. We hypothesized that αS in the ENS might play a role in the innate immune defenses of the human gastrointestinal (GI) tract. METHODS We immunostained endoscopic biopsies for αS from children with documented gastric and duodenal inflammation and intestinal allograft recipients who contracted norovirus. To determine whether αS exhibited immune-modulatory activity, we examined whether human αS induced leukocyte migration and dendritic cell maturation. FINDINGS We showed that the expression of αS in the enteric neurites of the upper GI tract of pediatric patients positively correlated with the degree of acute and chronic inflammation in the intestinal wall. In intestinal allograft subjects who were closely monitored for infection, expression of αS was induced during norovirus infection. We also demonstrated that both monomeric and oligomeric αS have potent chemoattractant activity, causing the migration of neutrophils and monocytes dependent on the presence of the integrin subunit, CD11b, and that both forms of αS stimulate dendritic cell maturation. INTERPRETATION These findings strongly suggest that αS is expressed within the human ENS to direct intestinal inflammation and implicates common GI infections in the pathogenesis of PD.
Collapse
Affiliation(s)
- Ethan Stolzenberg
- Department of Pathology, Section of Neuropathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Ying J, Delaglio F, Torchia DA, Bax A. Sparse multidimensional iterative lineshape-enhanced (SMILE) reconstruction of both non-uniformly sampled and conventional NMR data. J Biomol NMR 2017; 68:101-118. [PMID: 27866371 PMCID: PMC5438302 DOI: 10.1007/s10858-016-0072-7] [Citation(s) in RCA: 186] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 10/25/2016] [Indexed: 05/03/2023]
Abstract
Implementation of a new algorithm, SMILE, is described for reconstruction of non-uniformly sampled two-, three- and four-dimensional NMR data, which takes advantage of the known phases of the NMR spectrum and the exponential decay of underlying time domain signals. The method is very robust with respect to the chosen sampling protocol and, in its default mode, also extends the truncated time domain signals by a modest amount of non-sampled zeros. SMILE can likewise be used to extend conventional uniformly sampled data, as an effective multidimensional alternative to linear prediction. The program is provided as a plug-in to the widely used NMRPipe software suite, and can be used with default parameters for mainstream application, or with user control over the iterative process to possibly further improve reconstruction quality and to lower the demand on computational resources. For large data sets, the method is robust and demonstrated for sparsities down to ca 1%, and final all-real spectral sizes as large as 300 Gb. Comparison between fully sampled, conventionally processed spectra and randomly selected NUS subsets of this data shows that the reconstruction quality approaches the theoretical limit in terms of peak position fidelity and intensity. SMILE essentially removes the noise-like appearance associated with the point-spread function of signals that are a default of five-fold above the noise level, but impacts the actual thermal noise in the NMR spectra only minimally. Therefore, the appearance and interpretation of SMILE-reconstructed spectra is very similar to that of fully sampled spectra generated by Fourier transformation.
Collapse
Affiliation(s)
- Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Digestive and Diabetic and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Frank Delaglio
- Institute for Bioscience and Biotechnology Research, National Institute of Standards and Technology and the University of Maryland, Rockville, MD, 20850, USA
| | - Dennis A Torchia
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Digestive and Diabetic and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
| |
Collapse
|
47
|
Natarajan K, McShan AC, Jiang J, Kumirov VK, Wang R, Zhao H, Schuck P, Tilahun ME, Boyd LF, Ying J, Bax A, Margulies DH, Sgourakis NG. An allosteric site in the T-cell receptor Cβ domain plays a critical signalling role. Nat Commun 2017; 8:15260. [PMID: 28508865 PMCID: PMC5440810 DOI: 10.1038/ncomms15260] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 03/14/2017] [Indexed: 12/21/2022] Open
Abstract
The molecular mechanism through which the interaction of a clonotypic αβ T-cell receptor (TCR) with a peptide-loaded major histocompatibility complex (p/MHC) leads to T-cell activation is not yet fully understood. Here we exploit a high-affinity TCR (B4.2.3) to examine the structural changes that accompany binding to its p/MHC ligand (P18-I10/H2-Dd). In addition to conformational changes in complementarity-determining regions (CDRs) of the TCR seen in comparison of unliganded and bound X-ray structures, NMR characterization of the TCR β-chain dynamics reveals significant chemical shift effects in sites removed from the MHC-binding site. Remodelling of electrostatic interactions near the Cβ H3 helix at the membrane-proximal face of the TCR, a region implicated in interactions with the CD3 co-receptor, suggests a possible role for an allosteric mechanism in TCR signalling. The contribution of these TCR residues to signal transduction is supported by mutagenesis and T-cell functional assays.
Collapse
MESH Headings
- Allosteric Site/immunology
- Animals
- Complementarity Determining Regions/chemistry
- Complementarity Determining Regions/metabolism
- Crystallography, X-Ray
- Major Histocompatibility Complex/immunology
- Mice
- Molecular Dynamics Simulation
- Mutagenesis
- Peptides/metabolism
- Protein Binding/immunology
- Protein Domains/immunology
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Signal Transduction/immunology
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
Collapse
Affiliation(s)
- Kannan Natarajan
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Andrew C. McShan
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, USA
| | - Jiansheng Jiang
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Vlad K Kumirov
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, USA
| | - Rui Wang
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Huaying Zhao
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Peter Schuck
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Mulualem E. Tilahun
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Lisa F. Boyd
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - David H. Margulies
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Nikolaos G. Sgourakis
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, USA
| |
Collapse
|
48
|
Sgourakis N, Natarajan K, McShan A, Jiang J, Zhao H, Schuck P, Boyd LF, Tilahun ME, Ying J, Bax A, Margulies DH. An allosteric site in the T cell receptor β-chain constant domain plays a critical role in T cell signaling. The Journal of Immunology 2017. [DOI: 10.4049/jimmunol.198.supp.146.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
The molecular mechanism through which the interaction of a clonotypic αβ TCR with peptide/MHC (p/MHC) complexes leads to T cell activation is not yet fully understood. Here we exploit a high affinity TCR (B4.2.3) to examine the structural changes that accompany binding to its p/MHC ligand (P18-I10/H2-Dd) by combining crystallographic, NMR, and functional data. In addition to conformational changes in complementarity determining regions (CDR) of the TCR seen in comparison of unliganded and bound X-ray structures, NMR characterization of the TCR β chain dynamics reveals significant chemical shift effects in sites removed from the MHC binding site. In particular, a remodeling of electrostatic interactions near the Cβ H3 helix at the membrane-proximal face of the TCR, a region implicated in interactions with the CD3 co-receptor, suggests an allosteric mechanism for TCR signaling. The contribution of these TCR residues to signal transduction is supported by mutagenesis and T cell functional assays.
Collapse
|
49
|
Werner-Allen JW, Levine RL, Bax A. Superoxide is the critical driver of DOPAL autoxidation, lysyl adduct formation, and crosslinking of α-synuclein. Biochem Biophys Res Commun 2017; 487:281-286. [PMID: 28412346 DOI: 10.1016/j.bbrc.2017.04.050] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 04/11/2017] [Indexed: 02/08/2023]
Abstract
Parkinson's disease has long been associated with redox imbalance and oxidative stress in dopaminergic neurons. The catecholaldehyde hypothesis proposes that 3,4-dihydroxyphenylacetaldehyde (DOPAL), an obligate product of dopamine catabolism, is a central nexus in a network of pathways leading to disease-state neurodegeneration, owing to its toxicity and potent ability to oligomerize α-synuclein, the main component of protein aggregates in Lewy bodies. In this work we examine the connection between reactive oxygen species and DOPAL autoxidation. We show that superoxide propagates a chain reaction oxidation, and that this reaction is dramatically inhibited by superoxide dismutase. Moreover, superoxide dismutase prevents DOPAL from forming dicatechol pyrrole adducts with lysine and from covalently crosslinking α-synuclein. Given that superoxide is a major radical byproduct of impaired cellular respiration, our results provide a possible mechanistic link between mitochondrial dysfunction and synuclein aggregation in dopaminergic neurons.
Collapse
Affiliation(s)
- Jon W Werner-Allen
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, United States
| | - Rodney L Levine
- Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States.
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, United States.
| |
Collapse
|
50
|
Lee JH, Ying J, Bax A. Nuclear Magnetic Resonance Observation of α-Synuclein Membrane Interaction by Monitoring the Acetylation Reactivity of Its Lysine Side Chains. Biochemistry 2016; 55:4949-59. [PMID: 27455358 PMCID: PMC5015657 DOI: 10.1021/acs.biochem.6b00637] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The
interaction between α-synuclein (αS) protein and
lipid membranes is key to its role in synaptic vesicle homeostasis
and plays a role in initiating fibril formation, which is implicated
in Parkinson’s disease. The natural state of αS inside
the cell is generally believed to be intrinsically disordered, but
chemical cross-linking experiments provided evidence of a tetrameric
arrangement, which was reported to be rich in α-helical secondary
structure based on circular dichroism (CD). Cross-linking relies on
chemical modification of the protein’s Lys Cε amino groups, commonly by glutaraldehyde, or by disuccinimidyl glutarate
(DSG), with the latter agent preferred for cellular assays. We used
ultra-high-resolution homonuclear decoupled nuclear magnetic resonance
experiments to probe the reactivity of the 15 αS Lys residues
toward N-succinimidyl acetate, effectively half the
DSG cross-linker, which results in acetylation of Lys. The intensities
of both side chain and backbone amide signals of acetylated Lys residues
provide direct information about the reactivity, showing a difference
of a factor of 2.5 between the most reactive (K6) and the least reactive
(K102) residue. The presence of phospholipid vesicles decreases reactivity
of most Lys residues by up to an order of magnitude at high lipid:protein
stoichiometries (500:1), but only weakly at low ratios. The decrease
in Lys reactivity is found to be impacted by lipid composition, even
for vesicles that yield similar αS CD signatures. Our data provide
new insight into the αS–bilayer interaction, including
the pivotal state in which the available lipid surface is limited.
Protection of Lys Cε amino groups by αS–bilayer
interaction will strongly impact quantitative interpretation of DSG
cross-linking experiments.
Collapse
Affiliation(s)
- Jung Ho Lee
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
| |
Collapse
|