1
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Tran TT, Fanucci GE. Natural Polymorphisms D60E and I62V Stabilize a Closed Conformation in HIV-1 Protease in the Absence of an Inhibitor or Substrate. Viruses 2024; 16:236. [PMID: 38400012 PMCID: PMC10892587 DOI: 10.3390/v16020236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/18/2024] [Accepted: 01/24/2024] [Indexed: 02/25/2024] Open
Abstract
HIV infection remains a global health issue plagued by drug resistance and virological failure. Natural polymorphisms (NPs) contained within several African and Brazilian protease (PR) variants have been shown to induce a conformational landscape of more closed conformations compared to the sequence of subtype B prevalent in North America and Western Europe. Here we demonstrate through experimental pulsed EPR distance measurements and molecular dynamic (MD) simulations that the two common NPs D60E and I62V found within subtypes F and H can induce a closed conformation when introduced into HIV-1PR subtype B. Specifically, D60E alters the conformation in subtype B through the formation of a salt bridge with residue K43 contained within the nexus between the flap and hinge region of the HIV-1 PR fold. On the other hand, I62V modulates the packing of the hydrophobic cluster of the cantilever and fulcrum, also resulting in a more closed conformation.
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Affiliation(s)
| | - Gail E. Fanucci
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
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2
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Shihora A, Elias RD, Hammond JA, Ghirlando R, Deshmukh L. ALS Variants of Annexin A11's Proline-Rich Domain Impair Its S100A6-Mediated Fibril Dissolution. ACS Chem Neurosci 2023; 14:2583-2589. [PMID: 37433222 PMCID: PMC10401653 DOI: 10.1021/acschemneuro.3c00169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 07/05/2023] [Indexed: 07/13/2023] Open
Abstract
Mutations in the proline-rich domain (PRD) of annexin A11 are linked to amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease, and generate abundant neuronal A11 inclusions by an unknown mechanism. Here, we demonstrate that recombinant A11-PRD and its ALS-associated variants form liquidlike condensates that transform into β-sheet-rich amyloid fibrils. Surprisingly, these fibrils dissolved in the presence of S100A6, an A11 binding partner overexpressed in ALS. The ALS variants of A11-PRD showed longer fibrillization half-times and slower dissolution, even though their binding affinities for S100A6 were not significantly affected. These findings indicate a slower fibril-to-monomer exchange for these ALS variants, resulting in a decreased level of S100A6-mediated fibril dissolution. These ALS-A11 variants are thus more likely to remain aggregated despite their slower fibrillization.
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Affiliation(s)
- Aman Shihora
- Department
of Chemistry and Biochemistry, University
of California San Diego, La Jolla, California 92093, United States
| | - Ruben D. Elias
- Department
of Chemistry and Biochemistry, University
of California San Diego, La Jolla, California 92093, United States
| | - John A. Hammond
- Scripps
Research Biophysics and Biochemistry Core, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Rodolfo Ghirlando
- Laboratory
of Molecular Biology, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United States
| | - Lalit Deshmukh
- Department
of Chemistry and Biochemistry, University
of California San Diego, La Jolla, California 92093, United States
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3
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Khandave NP, Sekhar A, Vallurupalli P. Studying micro to millisecond protein dynamics using simple amide 15N CEST experiments supplemented with major-state R 2 and visible peak-position constraints. JOURNAL OF BIOMOLECULAR NMR 2023; 77:165-181. [PMID: 37300639 PMCID: PMC7615914 DOI: 10.1007/s10858-023-00419-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 05/10/2023] [Indexed: 06/12/2023]
Abstract
Over the last decade amide 15N CEST experiments have emerged as a popular tool to study protein dynamics that involves exchange between a 'visible' major state and sparsely populated 'invisible' minor states. Although initially introduced to study exchange between states that are in slow exchange with each other (typical exchange rates of, 10 to 400 s-1), they are now used to study interconversion between states on the intermediate to fast exchange timescale while still using low to moderate (5 to 350 Hz) 'saturating' B1 fields. The 15N CEST experiment is very sensitive to exchange as the exchange delay TEX can be quite long (~0.5 s) allowing for a large number of exchange events to occur making it a very powerful tool to detect minor sates populated ([Formula: see text]) to as low as 1%. When systems are in fast exchange and the 15N CEST data has to be described using a model that contains exchange, the exchange parameters are often poorly defined because the [Formula: see text] versus [Formula: see text] and [Formula: see text] versus exchange rate ([Formula: see text]) plots can be quite flat with shallow or no minima and the analysis of such 15N CEST data can lead to wrong estimates of the exchange parameters due to the presence of 'spurious' minima. Here we show that the inclusion of experimentally derived constraints on the intrinsic transverse relaxation rates and the inclusion of visible state peak-positions during the analysis of amide 15N CEST data acquired with moderate B1 values (~50 to ~350 Hz) results in convincing minima in the [Formula: see text] versus [Formula: see text] and the [Formula: see text] versus [Formula: see text] plots even when exchange occurs on the 100 μs timescale. The utility of this strategy is demonstrated on the fast-folding Bacillus stearothermophilus peripheral subunit binding domain that folds with a rate constant ~104 s-1. Here the analysis of 15N CEST data alone results in [Formula: see text] versus [Formula: see text] and [Formula: see text] versus [Formula: see text] plots that contain shallow minima, but the inclusion of visible-state peak positions and restraints on the intrinsic transverse relaxation rates of both states during the analysis of the 15N CEST data results in pronounced minima in the [Formula: see text] versus [Formula: see text] and [Formula: see text] versus [Formula: see text] plots and precise exchange parameters even in the fast exchange regime ([Formula: see text]~5). Using this strategy we find that the folding rate constant of PSBD is invariant (~10,500 s-1) from 33.2 to 42.9 °C while the unfolding rates (~70 to ~500 s-1) and unfolded state populations (~0.7 to ~4.3%) increase with temperature. The results presented here show that protein dynamics occurring on the 10 to 104 s-1 timescale can be studied using amide 15N CEST experiments.
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Affiliation(s)
- Nihar Pradeep Khandave
- Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, 500046, India
| | - Ashok Sekhar
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru, Karnataka, 560012, India
| | - Pramodh Vallurupalli
- Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, 500046, India.
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4
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Elias RD, Zhu Y, Su Q, Ghirlando R, Zhang J, Deshmukh L. Reversible phase separation of ESCRT protein ALIX through tyrosine phosphorylation. SCIENCE ADVANCES 2023; 9:eadg3913. [PMID: 37450591 PMCID: PMC10348681 DOI: 10.1126/sciadv.adg3913] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 06/14/2023] [Indexed: 07/18/2023]
Abstract
Cytokinetic abscission, the last step of cell division, is regulated by the ESCRT machinery. In response to mitotic errors, ESCRT proteins, namely, ALIX, CHMP4B, and CHMP4C, accumulate in the cytosolic compartments termed "abscission checkpoint bodies" (ACBs) to delay abscission and prevent tumorigenesis. ALIX contributes to the biogenesis and stability of ACBs via an unknown mechanism. We show that ALIX phase separates into nondynamic condensates in vitro and in vivo, mediated by the amyloidogenic portion of its proline-rich domain. ALIX condensates confined CHMP4 paralogs in vitro. These condensates dissolved and reformed upon reversible tyrosine phosphorylation of ALIX, mediated by Src kinase and PTP1B, and sequestration of CHMP4C altered their Src-mediated dissolution. NMR analysis revealed how ALIX triggers the activation of CHMP4 proteins, which is required for successful abscission. These results implicate ALIX's phase separation in the modulation of ACBs. This study also highlights how posttranslational modifications can control protein phase separation.
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Affiliation(s)
- Ruben D. Elias
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yingqi Zhu
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Qi Su
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Rodolfo Ghirlando
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jin Zhang
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Lalit Deshmukh
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
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5
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Ravera E, Gigli L, Fiorucci L, Luchinat C, Parigi G. The evolution of paramagnetic NMR as a tool in structural biology. Phys Chem Chem Phys 2022; 24:17397-17416. [PMID: 35849063 DOI: 10.1039/d2cp01838a] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Paramagnetic NMR data contain extremely accurate long-range information on metalloprotein structures and, when used in the frame of integrative structural biology approaches, they allow for the retrieval of structural details to a resolution that is not achievable using other techniques. Paramagnetic data thus represent an extremely powerful tool to refine protein models in solution, especially when coupled to X-ray or cryoelectron microscopy data, to monitor the formation of complexes and determine the relative arrangements of their components, and to highlight the presence of conformational heterogeneity. More recently, theoretical and computational advancements in quantum chemical calculations of paramagnetic NMR observables are progressively opening new routes in structural biology, because they allow for the determination of the structure within the coordination sphere of the metal center, thus acting as a loupe on sites that are difficult to observe but very important for protein function.
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Affiliation(s)
- Enrico Ravera
- Magnetic Resonance Center (CERM), University of Florence, via Luigi Sacconi 6, Sesto Fiorentino, 50019, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, via della Lastruccia 3, Sesto Fiorentino, 50019, Italy.,Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), via Luigi Sacconi 6, Sesto Fiorentino, 50019, Italy.
| | - Lucia Gigli
- Magnetic Resonance Center (CERM), University of Florence, via Luigi Sacconi 6, Sesto Fiorentino, 50019, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, via della Lastruccia 3, Sesto Fiorentino, 50019, Italy.,Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), via Luigi Sacconi 6, Sesto Fiorentino, 50019, Italy.
| | - Letizia Fiorucci
- Magnetic Resonance Center (CERM), University of Florence, via Luigi Sacconi 6, Sesto Fiorentino, 50019, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, via della Lastruccia 3, Sesto Fiorentino, 50019, Italy.,Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), via Luigi Sacconi 6, Sesto Fiorentino, 50019, Italy.
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM), University of Florence, via Luigi Sacconi 6, Sesto Fiorentino, 50019, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, via della Lastruccia 3, Sesto Fiorentino, 50019, Italy.,Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), via Luigi Sacconi 6, Sesto Fiorentino, 50019, Italy.
| | - Giacomo Parigi
- Magnetic Resonance Center (CERM), University of Florence, via Luigi Sacconi 6, Sesto Fiorentino, 50019, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, via della Lastruccia 3, Sesto Fiorentino, 50019, Italy.,Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), via Luigi Sacconi 6, Sesto Fiorentino, 50019, Italy.
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6
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Mechanistic roles of tyrosine phosphorylation in reversible amyloids, autoinhibition, and endosomal membrane association of ALIX. J Biol Chem 2021; 297:101328. [PMID: 34688656 PMCID: PMC8577116 DOI: 10.1016/j.jbc.2021.101328] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 10/05/2021] [Accepted: 10/06/2021] [Indexed: 11/26/2022] Open
Abstract
Human apoptosis-linked gene-2 interacting protein X (ALIX), a versatile adapter protein, regulates essential cellular processes by shuttling between late endosomal membranes and the cytosol, determined by its interactions with Src kinase. Here, we investigate the molecular basis of these transitions and the effects of tyrosine phosphorylation on the interplay between structure, assembly, and intramolecular and intermolecular interactions of ALIX. As evidenced by transmission electron microscopy, fluorescence and circular dichroism spectroscopy, the proline-rich domain of ALIX, which encodes binding epitopes of multiple cellular partners, formed rope-like β-sheet–rich reversible amyloid fibrils that dissolved upon Src-mediated phosphorylation and were restored on protein-tyrosine phosphatase 1B–mediated dephosphorylation of its conserved tyrosine residues. Analyses of the Bro1 domain of ALIX by solution NMR spectroscopy elucidated the conformational changes originating from its phosphorylation by Src and established that Bro1 binds to hyperphosphorylated proline-rich domain and to analogs of late endosomal membranes via its highly basic surface. These results uncover the autoinhibition mechanism that relocates ALIX to the cytosol and the diverse roles played by tyrosine phosphorylation in cellular and membrane functions of ALIX.
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7
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Samsudin F, Gan SKE, Bond PJ. The impact of Gag non-cleavage site mutations on HIV-1 viral fitness from integrative modelling and simulations. Comput Struct Biotechnol J 2020; 19:330-342. [PMID: 33425260 PMCID: PMC7779841 DOI: 10.1016/j.csbj.2020.12.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 01/19/2023] Open
Abstract
The high mutation rate in retroviruses is one of the leading causes of drug resistance. In human immunodeficiency virus type-1 (HIV-1), synergistic mutations in its protease and the protease substrate - the Group-specific antigen (Gag) polyprotein - work together to confer drug resistance against protease inhibitors and compensate the mutations affecting viral fitness. Some Gag mutations can restore Gag-protease binding, yet most Gag-protease correlated mutations occur outside of the Gag cleavage site. To investigate the molecular basis for this, we now report multiscale modelling approaches to investigate various sequentially cleaved Gag products in the context of clinically relevant mutations that occur outside of the cleavage sites, including simulations of the largest Gag proteolytic product in its viral membrane-bound state. We found that some mutations, such as G123E and H219Q, involve direct interaction with cleavage site residues to influence their local environment, while certain mutations in the matrix domain lead to the enrichment of lipids important for Gag targeting and assembly. Collectively, our results reveal why non-cleavage site mutations have far-reaching implications outside of Gag proteolysis, with important consequences for drugging Gag maturation intermediates and tackling protease inhibitor resistance.
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Affiliation(s)
- Firdaus Samsudin
- Bioinformatics Institute (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore
| | - Samuel Ken-En Gan
- Bioinformatics Institute (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore
- Antibody & Product Development Lab – Large Molecule Innovation, Experimental Drug Development Centre (A*STAR), 138670 Singapore, Singapore
- p53 Laboratory (A*STAR), 138648 Singapore, Singapore
| | - Peter J. Bond
- Bioinformatics Institute (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
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8
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Datir R, Kemp S, El Bouzidi K, Mlchocova P, Goldstein R, Breuer J, Towers GJ, Jolly C, Quiñones-Mateu ME, Dakum PS, Ndembi N, Gupta RK. In Vivo Emergence of a Novel Protease Inhibitor Resistance Signature in HIV-1 Matrix. mBio 2020; 11:e02036-20. [PMID: 33144375 PMCID: PMC7642677 DOI: 10.1128/mbio.02036-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/21/2020] [Indexed: 12/16/2022] Open
Abstract
Protease inhibitors (PIs) are the second- and last-line therapy for the majority of HIV-infected patients worldwide. Only around 20% of individuals who fail PI regimens develop major resistance mutations in protease. We sought to explore the role of mutations in gag-pro genotypic and phenotypic changes in viruses from six Nigerian patients who failed PI-based regimens without known drug resistance-associated protease mutations in order to identify novel determinants of PI resistance. Target enrichment and next-generation sequencing (NGS) with the Illumina MiSeq system were followed by haplotype reconstruction. Full-length Gag-protease gene regions were amplified from baseline (pre-PI) and virologic failure (VF) samples, sequenced, and used to construct gag-pro-pseudotyped viruses. Phylogenetic analysis was performed using maximum-likelihood methods. Susceptibility to lopinavir (LPV) and darunavir (DRV) was measured using a single-cycle replication assay. Western blotting was used to analyze Gag cleavage. In one of six participants (subtype CRF02_AG), we found 4-fold-lower LPV susceptibility in viral clones during failure of second-line treatment. A combination of four mutations (S126del, H127del, T122A, and G123E) in the p17 matrix of baseline virus generated a similar 4-fold decrease in susceptibility to LPV but not darunavir. These four amino acid changes were also able to confer LPV resistance to a subtype B Gag-protease backbone. Western blotting demonstrated significant Gag cleavage differences between sensitive and resistant isolates in the presence of drug. Resistant viruses had around 2-fold-lower infectivity than sensitive clones in the absence of drug. NGS combined with haplotype reconstruction revealed that resistant, less fit clones emerged from a minority population at baseline and thereafter persisted alongside sensitive fitter viruses. We used a multipronged genotypic and phenotypic approach to document emergence and temporal dynamics of a novel protease inhibitor resistance signature in HIV-1 matrix, revealing the interplay between Gag-associated resistance and fitness.
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Affiliation(s)
| | - Steven Kemp
- University College London, London, United Kingdom
| | | | - Petra Mlchocova
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | | | - Judy Breuer
- University College London, London, United Kingdom
| | | | - Clare Jolly
- University College London, London, United Kingdom
| | | | - Patrick S Dakum
- Institute for Human Virology, Abuja, Nigeria
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Nicaise Ndembi
- Institute for Human Virology, Abuja, Nigeria
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Ravindra K Gupta
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
- Africa Health Research Institute, Durban, South Africa
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9
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Schmidt T, Louis JM, Marius Clore G. Probing the Interaction between HIV-1 Protease and the Homodimeric p66/p66' Reverse Transcriptase Precursor by Double Electron-Electron Resonance EPR Spectroscopy. Chembiochem 2020; 21:3051-3055. [PMID: 32558168 PMCID: PMC7678880 DOI: 10.1002/cbic.202000263] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/16/2020] [Indexed: 11/08/2022]
Abstract
Following excision from the Gag-Pol polyprotein, HIV-1 reverse transcriptase is released as an asymmetric homodimer comprising two p66 subunits that are structurally dissimilar but identical in amino acid sequence. Subsequent cleavage of the RNase H domain from only one of the subunits, denoted p66', results in the formation of the mature p66/p51 enzyme in which catalytic activity resides in the p66 subunit, and the p51 subunit (derived from p66') provides a supporting structural scaffold. Here, we probe the interaction of the p66/p66' asymmetric reverse transcriptase precursor with HIV-1 protease by pulsed Q-band double electron-electron resonance EPR spectroscopy to measure distances between nitroxide labels introduced at surface-engineered cysteine residues. The data suggest that the flexible, exposed linker between the RNaseH and connection domains in the open state of the p66' subunit binds to the active site of protease in a configuration that is similar to that of extended peptide substrates.
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Affiliation(s)
- Thomas Schmidt
- Laboratory of Chemical Physics, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520 (USA)
| | - John M. Louis
- Laboratory of Chemical Physics, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520 (USA)
| | - G. Marius Clore
- Laboratory of Chemical Physics, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520 (USA)
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10
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Elias RD, Ma W, Ghirlando R, Schwieters CD, Reddy VS, Deshmukh L. Proline-rich domain of human ALIX contains multiple TSG101-UEV interaction sites and forms phosphorylation-mediated reversible amyloids. Proc Natl Acad Sci U S A 2020; 117:24274-24284. [PMID: 32917811 PMCID: PMC7533887 DOI: 10.1073/pnas.2010635117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Proline-rich domains (PRDs) are among the most prevalent signaling modules of eukaryotes but often unexplored by biophysical techniques as their heterologous recombinant expression poses significant difficulties. Using a "divide-and-conquer" approach, we present a detailed investigation of a PRD (166 residues; ∼30% prolines) belonging to a human protein ALIX, a versatile adaptor protein involved in essential cellular processes including ESCRT-mediated membrane remodeling, cell adhesion, and apoptosis. In solution, the N-terminal fragment of ALIX-PRD is dynamically disordered. It contains three tandem sequentially similar proline-rich motifs that compete for a single binding site on its signaling partner, TSG101-UEV, as evidenced by heteronuclear NMR spectroscopy. Global fitting of relaxation dispersion data, measured as a function of TSG101-UEV concentration, allowed precise quantitation of these interactions. In contrast to the soluble N-terminal portion, the C-terminal tyrosine-rich fragment of ALIX-PRD forms amyloid fibrils and viscous gels validated using dye-binding assays with amyloid-specific probes, congo red and thioflavin T (ThT), and visualized by transmission electron microscopy. Remarkably, fibrils dissolve at low temperatures (2 to 6 °C) or upon hyperphosphorylation with Src kinase. Aggregation kinetics monitored by ThT fluorescence shows that charge repulsion dictates phosphorylation-mediated fibril dissolution and that the hydrophobic effect drives fibril formation. These data illuminate the mechanistic interplay between interactions of ALIX-PRD with TSG101-UEV and polymerization of ALIX-PRD and its central role in regulating ALIX function. This study also demonstrates the broad functional repertoires of PRDs and uncovers the impact of posttranslational modifications in the modulation of reversible amyloids.
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Affiliation(s)
- Ruben D Elias
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093
| | - Wen Ma
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093
| | - Rodolfo Ghirlando
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Charles D Schwieters
- Division of Computational Biosciences, Center for Information Technology, National Institutes of Health, Bethesda, MD 20892
| | - Vijay S Reddy
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037
| | - Lalit Deshmukh
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093;
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11
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Paramagnetic NMR Spectroscopy Is a Tool to Address Reactivity, Structure, and Protein–Protein Interactions of Metalloproteins: The Case of Iron–Sulfur Proteins. MAGNETOCHEMISTRY 2020. [DOI: 10.3390/magnetochemistry6040046] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The study of cellular machineries responsible for the iron–sulfur (Fe–S) cluster biogenesis has led to the identification of a large number of proteins, whose importance for life is documented by an increasing number of diseases linked to them. The labile nature of Fe–S clusters and the transient protein–protein interactions, occurring during the various steps of the maturation process, make their structural characterization in solution particularly difficult. Paramagnetic nuclear magnetic resonance (NMR) has been used for decades to characterize chemical composition, magnetic coupling, and the electronic structure of Fe–S clusters in proteins; it represents, therefore, a powerful tool to study the protein–protein interaction networks of proteins involving into iron–sulfur cluster biogenesis. The optimization of the various NMR experiments with respect to the hyperfine interaction will be summarized here in the form of a protocol; recently developed experiments for measuring longitudinal and transverse nuclear relaxation rates in highly paramagnetic systems will be also reviewed. Finally, we will address the use of extrinsic paramagnetic centers covalently bound to diamagnetic proteins, which contributed over the last twenty years to promote the applications of paramagnetic NMR well beyond the structural biology of metalloproteins.
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12
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Collier DA, Monit C, Gupta RK. The Impact of HIV-1 Drug Escape on the Global Treatment Landscape. Cell Host Microbe 2019; 26:48-60. [PMID: 31295424 DOI: 10.1016/j.chom.2019.06.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The rising prevalence of HIV drug resistance (HIVDR) could threaten gains made in combating the HIV epidemic and compromise the 90-90-90 target proposed by United Nations Programme on HIV/AIDS (UNAIDS) to have achieved virological suppression in 90% of all persons receiving antiretroviral therapy (ART) by the year 2020. HIVDR has implications for the persistence of HIV, the selection of current and future ART drug regimens, and strategies of vaccine and cure development. Focusing on drug classes that are in clinical use, this Review critically summarizes what is known about the mechanisms the virus utilizes to escape drug control. Armed with this knowledge, strategies to limit the expansion of HIVDR are proposed.
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Affiliation(s)
- D A Collier
- Division of Infection and Immunity, University College London, London, UK
| | - C Monit
- Division of Infection and Immunity, University College London, London, UK
| | - R K Gupta
- Department of Medicine, University of Cambridge, Cambridge, UK.
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13
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Henes M, Lockbaum GJ, Kosovrasti K, Leidner F, Nachum GS, Nalivaika EA, Lee SK, Spielvogel E, Zhou S, Swanstrom R, Bolon DN, Yilmaz NK, Schiffer CA. Picomolar to Micromolar: Elucidating the Role of Distal Mutations in HIV-1 Protease in Conferring Drug Resistance. ACS Chem Biol 2019; 14:2441-2452. [PMID: 31361460 PMCID: PMC6941144 DOI: 10.1021/acschembio.9b00370] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Drug resistance continues to be a growing global problem. The efficacy of small molecule inhibitors is threatened by pools of genetic diversity in all systems, including antibacterials, antifungals, cancer therapeutics, and antivirals. Resistant variants often include combinations of active site mutations and distal "secondary" mutations, which are thought to compensate for losses in enzymatic activity. HIV-1 protease is the ideal model system to investigate these combinations and underlying molecular mechanisms of resistance. Darunavir (DRV) binds wild-type (WT) HIV-1 protease with a potency of <5 pM, but we have identified a protease variant that loses potency to DRV 150 000-fold, with 11 mutations in and outside the active site. To elucidate the roles of these mutations in DRV resistance, we used a multidisciplinary approach, combining enzymatic assays, crystallography, and molecular dynamics simulations. Analysis of protease variants with 1, 2, 4, 8, 9, 10, and 11 mutations showed that the primary active site mutations caused ∼50-fold loss in potency (2 mutations), while distal mutations outside the active site further decreased DRV potency from 13 nM (8 mutations) to 0.76 μM (11 mutations). Crystal structures and simulations revealed that distal mutations induce subtle changes that are dynamically propagated through the protease. Our results reveal that changes remote from the active site directly and dramatically impact the potency of the inhibitor. Moreover, we find interdependent effects of mutations in conferring high levels of resistance. These mechanisms of resistance are likely applicable to many other quickly evolving drug targets, and the insights may have implications for the design of more robust inhibitors.
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Affiliation(s)
- Mina Henes
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, United States
| | - Gordon J. Lockbaum
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, United States
| | - Klajdi Kosovrasti
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, United States
| | - Florian Leidner
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, United States
| | - Gily S. Nachum
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, United States
| | - Ellen A. Nalivaika
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, United States
| | - Sook-Kyung Lee
- Department of Biochemistry and Biophysics and the UNC Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Ean Spielvogel
- Department of Biochemistry and Biophysics and the UNC Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Shuntai Zhou
- Department of Biochemistry and Biophysics and the UNC Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Ronald Swanstrom
- Department of Biochemistry and Biophysics and the UNC Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Daniel N.A. Bolon
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, United States
| | - Nese Kurt Yilmaz
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, United States,Corresponding authors Celia A. Schiffer: Phone: +1 508 856 8008; , Nese Kurt Yilmaz: Phone: +1 508 856 1867;
| | - Celia A. Schiffer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, United States,Corresponding authors Celia A. Schiffer: Phone: +1 508 856 8008; , Nese Kurt Yilmaz: Phone: +1 508 856 1867;
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14
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Miller Jenkins LM, Paine EL, Deshmukh L, Nikolayevskiy H, Lyons GC, Scerba MT, Rosenker KG, Luecke HF, Louis JM, Chertova E, Gorelick RJ, Ott DE, Clore GM, Appella DH. Inhibition of HIV Maturation via Selective Unfolding and Cross-Linking of Gag Polyprotein by a Mercaptobenzamide Acetylator. J Am Chem Soc 2019; 141:8327-8338. [PMID: 31042030 PMCID: PMC8496520 DOI: 10.1021/jacs.9b02743] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
For HIV to become infectious, any new virion produced from an infected cell must undergo a maturation process that involves the assembly of viral polyproteins Gag and Gag-Pol at the membrane surface. The self-assembly of these viral proteins drives formation of a new viral particle as well as the activation of HIV protease, which is needed to cleave the polyproteins so that the final core structure of the virus will properly form. Molecules that interfere with HIV maturation will prevent any new virions from infecting additional cells. In this manuscript, we characterize the unique mechanism by which a mercaptobenzamide thioester small molecule (SAMT-247) interferes with HIV maturation via a series of selective acetylations at highly conserved cysteine and lysine residues in Gag and Gag-Pol polyproteins. The results provide the first insights into how acetylation can be utilized to perturb the process of HIV maturation and reveal a new strategy to limit the infectivity of HIV.
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Affiliation(s)
- Lisa M. Miller Jenkins
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Elliott L. Paine
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Lalit Deshmukh
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, United States
| | - Herman Nikolayevskiy
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, United States
| | - Gaelyn C. Lyons
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Michael T. Scerba
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, United States
| | - Kara George Rosenker
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, United States
| | - Hans F. Luecke
- Advanced Mass Spectrometry Core, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, United States
| | - John M. Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, United States
| | - Elena Chertova
- AIDS and Cancer Virus Program, Leidos Biomedical Research Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, United States
| | - Robert J. Gorelick
- AIDS and Cancer Virus Program, Leidos Biomedical Research Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, United States
| | - David E. Ott
- AIDS and Cancer Virus Program, Leidos Biomedical Research Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, United States
| | - G. Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, United States
| | - Daniel H. Appella
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, United States
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15
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Coetzer M, Ledingham L, Diero L, Kemboi E, Orido M, Kantor R. Gp41 and Gag amino acids linked to HIV-1 protease inhibitor-based second-line failure in HIV-1 subtype A from Western Kenya. J Int AIDS Soc 2018; 20. [PMID: 29098809 PMCID: PMC5810327 DOI: 10.1002/jia2.25024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 10/05/2017] [Indexed: 12/28/2022] Open
Abstract
Introduction Failure of protease‐inhibitor (PI)‐based second‐line antiretroviral therapy (ART) with medication adherence but no protease drug resistance mutations (DRMs) is not well understood. This study investigated the involvement of gp41 and gag as alternative mechanisms, not captured by conventional resistance testing and particularly relevant in resource‐limited settings where third‐line ART is limited. Methods We evaluated gp41 and gag for unique amino acids in seven subtype A infected Kenyans failing second‐line therapy with no PI resistance yet detectable lopinavir (query dataset), compared to seven similar‐setting patients with PI resistance or undetectable lopinavir and 69 publically available subtype A Kenyan whole‐genomes sequences. Results Three gp41 (607T, 641L, 721I) and four gag (124S, 143V, 339P, 357S) amino acids were significantly more frequent in the query dataset compared to the other datasets, with significantly high co‐occurrence. Conclusion The genotypic analysis of a unique group of HIV‐1 subtype A infected patients, identified seven amino acids that could potentially contribute to a multi‐gene mechanism of PI‐based ART failure in the absence of PI DR mutations.
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Affiliation(s)
- Mia Coetzer
- Division of Infectious Diseases, Brown University, Providence, RI, USA
| | - Lauren Ledingham
- Division of Infectious Diseases, Brown University, Providence, RI, USA
| | - Lameck Diero
- Academic Model Providing Access to Healthcare (AMPATH), Eldoret, Kenya.,Department of Medicine, School of Medicine, College of Health Sciences, Moi University, Eldoret, Kenya
| | - Emmanuel Kemboi
- Academic Model Providing Access to Healthcare (AMPATH), Eldoret, Kenya
| | - Millicent Orido
- Academic Model Providing Access to Healthcare (AMPATH), Eldoret, Kenya
| | - Rami Kantor
- Division of Infectious Diseases, Brown University, Providence, RI, USA
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16
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Paramagnetic NMR as a new tool in structural biology. Emerg Top Life Sci 2018; 2:19-28. [DOI: 10.1042/etls20170084] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 12/19/2017] [Accepted: 12/20/2017] [Indexed: 12/25/2022]
Abstract
NMR (nuclear magnetic resonance) investigation through the exploitation of paramagnetic effects is passing from an approach limited to few specialists in the field to a generally applicable method that must be considered, especially for the characterization of systems hardly affordable with other techniques. This is mostly due to the fact that paramagnetic data are long range in nature, thus providing information for the structural and dynamic characterization of complex biomolecular architectures in their native environment. On the other hand, this information usually needs to be complemented by data from other sources. Integration of paramagnetic NMR with other techniques, and the development of protocols for a joint analysis of all available data, is fundamental for achieving a comprehensive characterization of complex biological systems. We describe here a few examples of the new possibilities offered by paramagnetic data used in integrated structural approaches.
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17
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Binding kinetics and substrate selectivity in HIV-1 protease-Gag interactions probed at atomic resolution by chemical exchange NMR. Proc Natl Acad Sci U S A 2017; 114:E9855-E9862. [PMID: 29087351 DOI: 10.1073/pnas.1716098114] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The conversion of immature noninfectious HIV-1 particles to infectious virions is dependent upon the sequential cleavage of the precursor group-specific antigen (Gag) polyprotein by HIV-1 protease. The precise mechanism whereby protease recognizes distinct Gag cleavage sites, located in the intrinsically disordered linkers connecting the globular domains of Gag, remains unclear. Here, we probe the dynamics of the interaction of large fragments of Gag and various variants of protease (including a drug resistant construct) using Carr-Purcell-Meiboom-Gill relaxation dispersion and chemical exchange saturation transfer NMR experiments. We show that the conformational dynamics within the flaps of HIV-1 protease that form the lid over the catalytic cleft play a significant role in substrate specificity and ordered Gag processing. Rapid interconversion between closed and open protease flap conformations facilitates the formation of a transient, sparsely populated productive complex between protease and Gag substrates. Flap closure traps the Gag cleavage sites within the catalytic cleft of protease. Modulation of flap opening through protease-Gag interactions fine-tunes the lifetime of the productive complex and hence the likelihood of Gag proteolysis. A productive complex can also be formed in the presence of a noncognate substrate but is short-lived owing to lack of optimal complementarity between the active site cleft of protease and the substrate, resulting in rapid flap opening and substrate release, thereby allowing protease to differentiate between cognate and noncognate substrates.
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18
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Manasa J, Varghese V, Pond SLK, Rhee SY, Tzou PL, Fessel WJ, Jang KS, White E, Rögnvaldsson T, Katzenstein DA, Shafer RW. Evolution of gag and gp41 in Patients Receiving Ritonavir-Boosted Protease Inhibitors. Sci Rep 2017; 7:11559. [PMID: 28912582 PMCID: PMC5599673 DOI: 10.1038/s41598-017-11893-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 08/31/2017] [Indexed: 11/15/2022] Open
Abstract
Several groups have proposed that genotypic determinants in gag and the gp41 cytoplasmic domain (gp41-CD) reduce protease inhibitor (PI) susceptibility without PI-resistance mutations in protease. However, no gag and gp41-CD mutations definitively responsible for reduced PI susceptibility have been identified in individuals with virological failure (VF) while receiving a boosted PI (PI/r)-containing regimen. To identify gag and gp41 mutations under selective PI pressure, we sequenced gag and/or gp41 in 61 individuals with VF on a PI/r (n = 40) or NNRTI (n = 20) containing regimen. We quantified nonsynonymous and synonymous changes in both genes and identified sites exhibiting signal for directional or diversifying selection. We also used published gag and gp41 polymorphism data to highlight mutations displaying a high selection index, defined as changing from a conserved to an uncommon amino acid. Many amino acid mutations developed in gag and in gp41-CD in both the PI- and NNRTI-treated groups. However, in neither gene, were there discernable differences between the two groups in overall numbers of mutations, mutations displaying evidence of diversifying or directional selection, or mutations with a high selection index. If gag and/or gp41 encode PI-resistance mutations, they may not be confined to consistent mutations at a few sites.
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Affiliation(s)
- Justen Manasa
- Division of Infectious Diseases, Department of Medicine Stanford University, Stanford, CA, USA
| | - Vici Varghese
- Division of Infectious Diseases, Department of Medicine Stanford University, Stanford, CA, USA
| | | | - Soo-Yon Rhee
- Division of Infectious Diseases, Department of Medicine Stanford University, Stanford, CA, USA
| | - Philip L Tzou
- Division of Infectious Diseases, Department of Medicine Stanford University, Stanford, CA, USA
| | - W Jeffrey Fessel
- Department of Internal Medicine, Kaiser Permanente Medical Care Program - Northern California, San Francisco, CA, United States
| | - Karen S Jang
- Division of Infectious Diseases, Department of Medicine Stanford University, Stanford, CA, USA
| | - Elizabeth White
- Division of Infectious Diseases, Department of Medicine Stanford University, Stanford, CA, USA
| | | | - David A Katzenstein
- Division of Infectious Diseases, Department of Medicine Stanford University, Stanford, CA, USA
| | - Robert W Shafer
- Division of Infectious Diseases, Department of Medicine Stanford University, Stanford, CA, USA.
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19
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Codoñer FM, Peña R, Blanch-Lombarte O, Jimenez-Moyano E, Pino M, Vollbrecht T, Clotet B, Martinez-Picado J, Draenert R, Prado JG. Gag-protease coevolution analyses define novel structural surfaces in the HIV-1 matrix and capsid involved in resistance to Protease Inhibitors. Sci Rep 2017. [PMID: 28623276 PMCID: PMC5473930 DOI: 10.1038/s41598-017-03260-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Despite the major role of Gag in establishing resistance of HIV-1 to protease inhibitors (PIs), very limited data are available on the total contribution of Gag residues to resistance to PIs. To identify in detail Gag residues and structural interfaces associated with the development of HIV-1 resistance to PIs, we traced viral evolution under the pressure of PIs using Gag-protease single genome sequencing and coevolution analysis of protein sequences in 4 patients treated with PIs over a 9-year period. We identified a total of 38 Gag residues correlated with the protease, 32 of which were outside Gag cleavage sites. These residues were distributed in 23 Gag-protease groups of coevolution, with the viral matrix and the capsid represented in 87% and 52% of the groups. In addition, we uncovered the distribution of Gag correlated residues in specific protein surfaces of the inner face of the viral matrix and at the Cyclophilin A binding loop of the capsid. In summary, our findings suggest a tight interdependency between Gag structural proteins and the protease during the development of resistance of HIV-1 to PIs.
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Affiliation(s)
- Francisco M Codoñer
- Lifesequencing SL, Paterna, Spain.,Universidad Catolica de Valencia, Valencia, Spain
| | - Ruth Peña
- AIDS Research Institute IrsiCaixa, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Oscar Blanch-Lombarte
- AIDS Research Institute IrsiCaixa, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Esther Jimenez-Moyano
- AIDS Research Institute IrsiCaixa, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Maria Pino
- AIDS Research Institute IrsiCaixa, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Thomas Vollbrecht
- Veterans Affairs San Diego Healthcare System, San Diego, California, USA.,University of California San Diego, La Jolla, California, USA
| | - Bonaventura Clotet
- AIDS Research Institute IrsiCaixa, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.,Universitat de Vic-Universitat Central de Catalunya, Vic, Spain
| | - Javier Martinez-Picado
- AIDS Research Institute IrsiCaixa, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.,Universitat de Vic-Universitat Central de Catalunya, Vic, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Rika Draenert
- Medizinische Poliklinik, Klinikum der Ludwig-Maximilians-Universität München, Munich, Germany
| | - Julia G Prado
- AIDS Research Institute IrsiCaixa, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.
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20
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Vallurupalli P, Sekhar A, Yuwen T, Kay LE. Probing conformational dynamics in biomolecules via chemical exchange saturation transfer: a primer. JOURNAL OF BIOMOLECULAR NMR 2017; 67:243-271. [PMID: 28317074 DOI: 10.1007/s10858-017-0099-4] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 02/20/2017] [Indexed: 05/25/2023]
Abstract
Although Chemical Exchange Saturation Transfer (CEST) type NMR experiments have been used to study chemical exchange processes in molecules since the early 1960s, there has been renewed interest in the past several years in using this approach to study biomolecular conformational dynamics. The methodology is particularly powerful for the study of sparsely populated, transiently formed conformers that are recalcitrant to investigation using traditional biophysical tools, and it is complementary to relaxation dispersion and magnetization transfer experiments that have traditionally been used to study chemical exchange processes. Here we discuss the concepts behind the CEST experiment, focusing on practical aspects as well, we review some of the pulse sequences that have been developed to characterize protein and RNA conformational dynamics, and we discuss a number of examples where the CEST methodology has provided important insights into the role of dynamics in biomolecular function.
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Affiliation(s)
| | - Ashok Sekhar
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, ON, Canada
| | - Tairan Yuwen
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, ON, Canada
| | - Lewis E Kay
- Departments of Molecular Genetics, Biochemistry and Chemistry, University of Toronto, Toronto, ON, Canada.
- Hospital for Sick Children, Program in Molecular Structure and Function, Toronto, ON, Canada.
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