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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Hossain MI, Asha AT, Hossain MA, Mahmud S, Chowdhury K, Mohiuddin RB, Nahar N, Sarker S, Napis S, Hossain MS, Mohiuddin A. Investigating the role of hypothetical protein (AAB33144.1) in HIV-1 virus pathogenicity: A comparative study with FDA-Approved inhibitor compounds through In silico analysis and molecular docking. Heliyon 2024; 10:e23183. [PMID: 38163140 PMCID: PMC10755284 DOI: 10.1016/j.heliyon.2023.e23183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Accepted: 11/28/2023] [Indexed: 01/03/2024] Open
Abstract
Aim and objective Due to the a lot of unexplored proteins in HIV-1, this research aimed to explore the functional roles of a hypothetical protein (AAB33144.1) that might play a key role in HIV-1 pathogenicity. Methods The homologous protein was identified along with building and validating the 3D structure by searching several bioinformatics tools. Results Retroviral aspartyl protease and retropepsin like functional domains and motifs, folding pattern (cupredoxins), and subcellular localization in cytoplasmic membrane were determined as biological activity. Besides, the functional annotation revealed that the chosen hypothetical protein possessed protease-like activity. To validate our generated protein 3D structure, molecular docking was performed with five compounds where nelfinavir showed (-8.2 kcal/mol) best binding affinity against HXB2 viral protease (PDB ID: 7SJX) and main protease (PDB ID: 4EYR) protein. Conclusions This study suggests that the annotated hypothetical protein related to protease action, which may be useful in viral genetics and drug discovery.
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Affiliation(s)
- Md. Imran Hossain
- Department of Biotechnology and Genetic Engineering, Mawlana Bhashani Science and Technology University, Tangail, 1902, Bangladesh
| | - Anika Tabassum Asha
- Department of Biotechnology and Genetic Engineering, Mawlana Bhashani Science and Technology University, Tangail, 1902, Bangladesh
| | - Md. Arju Hossain
- Department of Biotechnology and Genetic Engineering, Mawlana Bhashani Science and Technology University, Tangail, 1902, Bangladesh
| | - Shahin Mahmud
- Department of Biotechnology and Genetic Engineering, Mawlana Bhashani Science and Technology University, Tangail, 1902, Bangladesh
| | - Kamal Chowdhury
- Biology Department, Claflin University, 400 Magnolia St, Orangeburg, SC 29115, USA
| | - Ramisa Binti Mohiuddin
- Department of Pharmacy, Mawlana Bhashani Science and Technology University, Tangail, 1902, Bangladesh
| | - Nazneen Nahar
- Department of Biotechnology and Genetic Engineering, Mawlana Bhashani Science and Technology University, Tangail, 1902, Bangladesh
| | - Saborni Sarker
- Department of Biotechnology and Genetic Engineering, Mawlana Bhashani Science and Technology University, Tangail, 1902, Bangladesh
| | - Suhaimi Napis
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor D.E., Malaysia
| | - Md Sanower Hossain
- Centre for Sustainability of Mineral and Resource Recovery Technology (Pusat SMaRRT), Universiti Malaysia Pahang Al-Sultan Abdullah, Kuantan 26300, Malaysia
| | - A.K.M. Mohiuddin
- Department of Biotechnology and Genetic Engineering, Mawlana Bhashani Science and Technology University, Tangail, 1902, Bangladesh
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3
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Wong-Sam A, Wang YF, Kneller DW, Kovalevsky AY, Ghosh AK, Harrison RW, Weber IT. HIV-1 protease with 10 lopinavir and darunavir resistance mutations exhibits altered inhibition, structural rearrangements and extreme dynamics. J Mol Graph Model 2022; 117:108315. [PMID: 36108568 PMCID: PMC10091457 DOI: 10.1016/j.jmgm.2022.108315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/17/2022] [Accepted: 08/21/2022] [Indexed: 01/14/2023]
Abstract
Antiretroviral drug resistance is a therapeutic obstacle for people with HIV. HIV protease inhibitors darunavir and lopinavir are recommended for resistant infections. We characterized a protease mutant (PR10x) derived from a highly resistant clinical isolate including 10 mutations associated with resistance to lopinavir and darunavir. Compared to the wild-type protease, PR10x exhibits ∼3-fold decrease in catalytic efficiency and Ki values of 2-3 orders of magnitude worse for darunavir, lopinavir, and potent investigational inhibitor GRL-519. Crystal structures of the mutant were solved in a ligand-free form and in complex with GRL-519. The structures show altered interactions in the active site, flap-core interface, hydrophobic core, hinge region, and 80s loop compared to the corresponding wild-type protease structures. The ligand-free crystal structure exhibits a highly curled flap conformation which may amplify drug resistance. Molecular dynamics simulations performed for 1 μs on ligand-free dimers showed extremely large fluctuations in the flaps for PR10x compared to equivalent simulations on PR with a single L76V mutation or wild-type protease. This analysis offers insight about the synergistic effects of mutations in highly resistant variants.
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Affiliation(s)
- Andres Wong-Sam
- Department of Biology, Georgia State University, Atlanta, GA, 30303, USA
| | - Yuan-Fang Wang
- Department of Biology, Georgia State University, Atlanta, GA, 30303, USA
| | - Daniel W Kneller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Andrey Y Kovalevsky
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Arun K Ghosh
- Department of Chemistry and Department of Medicinal Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Robert W Harrison
- Department of Biology, Georgia State University, Atlanta, GA, 30303, USA; Department of Computer Science, Georgia State University, Atlanta, GA, 30303, USA
| | - Irene T Weber
- Department of Biology, Georgia State University, Atlanta, GA, 30303, USA; Department of Chemistry, Georgia State University, Atlanta, GA, 30303, USA.
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4
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Precursors of Viral Proteases as Distinct Drug Targets. Viruses 2021; 13:v13101981. [PMID: 34696411 PMCID: PMC8537868 DOI: 10.3390/v13101981] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/25/2021] [Accepted: 09/28/2021] [Indexed: 12/16/2022] Open
Abstract
Viral proteases are indispensable for successful virion maturation, thus making them a prominent drug target. Their enzyme activity is tightly spatiotemporally regulated by expression in the precursor form with little or no activity, followed by activation via autoprocessing. These cleavage events are frequently triggered upon transportation to a specific compartment inside the host cell. Typically, precursor oligomerization or the presence of a co-factor is needed for activation. A detailed understanding of these mechanisms will allow ligands with non-canonical mechanisms of action to be designed, which would specifically modulate the initial irreversible steps of viral protease autoactivation. Binding sites exclusive to the precursor, including binding sites beyond the protease domain, can be exploited. Both inhibition and up-regulation of the proteolytic activity of viral proteases can be detrimental for the virus. All these possibilities are discussed using examples of medically relevant viruses including herpesviruses, adenoviruses, retroviruses, picornaviruses, caliciviruses, togaviruses, flaviviruses, and coronaviruses.
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5
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Burnaman SH, Kneller DW, Wang YF, Kovalevsky A, Weber IT. Revertant mutation V48G alters conformational dynamics of highly drug resistant HIV protease PRS17. J Mol Graph Model 2021; 108:108005. [PMID: 34419931 DOI: 10.1016/j.jmgm.2021.108005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/06/2021] [Accepted: 08/08/2021] [Indexed: 11/27/2022]
Abstract
Drug resistance is a serious problem for controlling the HIV/AIDS pandemic. Current antiviral drugs show several orders of magnitude worse inhibition of highly resistant clinical variant PRS17 of HIV-1 protease compared with wild-type protease. We have analyzed the effects of a common resistance mutation G48V in the flexible flaps of the protease by assessing the revertant PRS17V48G for changes in enzyme kinetics, inhibition, structure, and dynamics. Both PRS17 and the revertant showed about 10-fold poorer catalytic efficiency than wild-type enzyme (0.55 and 0.39 μM-1min-1 compared to 6.3 μM-1min-1). Clinical inhibitors, amprenavir and darunavir, showed 2-fold and 8-fold better inhibition, respectively, of the revertant than of PRS17, although the inhibition constants for PRS17V48G were still 25 to 1,200-fold worse than for wild-type protease. Crystal structures of inhibitor-free revertant and amprenavir complexes with revertant and PRS17 were solved at 1.3-1.5 Å resolution. The amprenavir complexes of PRS17V48G and PRS17 showed no significant differences in the interactions with inhibitor, although changes were observed in the conformation of Phe53 and the interactions of the flaps. The inhibitor-free structure of the revertant showed flaps in an open conformation, however, the flap tips do not have the unusual curled conformation seen in inhibitor-free PRS17. Molecular dynamics simulations were run for 1 μs on the two inhibitor-free mutants and wild-type protease. PRS17 exhibited higher conformational fluctuations than the revertant, while the wild-type protease adopted the closed conformation and showed the least variation. The second half of the simulations captured the transition of the flaps of PRS17 from a closed to a semi-open state, whereas the flaps of PRS17V48G tucked into the active site and the wild-type protease retained the closed conformation. These results suggest that mutation G48V contributes to drug resistance by altering the conformational dynamics of the flaps.
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Affiliation(s)
| | - Daniel W Kneller
- Neutron Scattering Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN, 37831, USA
| | - Yuan-Fang Wang
- Department of Biology, Georgia State University, Atlanta, GA, USA
| | - Andrey Kovalevsky
- Neutron Scattering Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN, 37831, USA
| | - Irene T Weber
- Department of Biology, Georgia State University, Atlanta, GA, USA.
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6
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Laville P, Petitjean M, Regad L. Structural Impacts of Drug-Resistance Mutations Appearing in HIV-2 Protease. Molecules 2021; 26:molecules26030611. [PMID: 33503916 PMCID: PMC7865771 DOI: 10.3390/molecules26030611] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/15/2021] [Accepted: 01/19/2021] [Indexed: 11/16/2022] Open
Abstract
The use of antiretroviral drugs is accompanied by the emergence of HIV-2 resistances. Thus, it is important to elucidate the mechanisms of resistance to antiretroviral drugs. Here, we propose a structural analysis of 31 drug-resistant mutants of HIV-2 protease (PR2) that is an important target against HIV-2 infection. First, we modeled the structures of each mutant. We then located structural shifts putatively induced by mutations. Finally, we compared wild-type and mutant inhibitor-binding pockets and interfaces to explore the impacts of these induced structural deformations on these two regions. Our results showed that one mutation could induce large structural rearrangements in side-chain and backbone atoms of mutated residue, in its vicinity or further. Structural deformations observed in side-chain atoms are frequent and of greater magnitude, that confirms that to fight drug resistance, interactions with backbone atoms should be favored. We showed that these observed structural deformations modify the conformation, volume, and hydrophobicity of the binding pocket and the composition and size of the PR2 interface. These results suggest that resistance mutations could alter ligand binding by modifying pocket properties and PR2 stability by impacting its interface. Our results reinforce the understanding of the effects of mutations that occurred in PR2 and the different mechanisms of PR2 resistance.
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7
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Tran TT, Liu Z, Fanucci GE. Conformational landscape of non-B variants of HIV-1 protease: A pulsed EPR study. Biochem Biophys Res Commun 2020; 532:219-224. [PMID: 32863004 DOI: 10.1016/j.bbrc.2020.08.030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 08/12/2020] [Indexed: 02/02/2023]
Abstract
HIV infection is a global health epidemic with current FDA-approved HIV-1 Protease inhibitors (PIs) designed against subtype B protease, yet they are used in HIV treatment world-wide regardless of patient HIV classification. In this study, double electron-electron resonance (DEER) electron paramagnetic resonance (EPR) spectroscopy was utilized to gain insights in how natural polymorphisms in several African and Brazilian protease (PR) variants affect the conformational landscape both in the absence and presence of inhibitors. Findings show that Subtypes F and H HIV-1 PR adopt a primarily closed conformation in the unbound state with two secondary mutations, D60E and I62V, postulated to be responsible for the increased probability for closed conformation. In contrast, subtype D, CRF_AG, and CRF_BF HIV-1 PR adopt a primarily semi-open conformation, as observed for PI-naïve-subtype B when unbound by substrate or inhibitor. The impact that inhibitor binding has on shifting the conformational land scape of these variants is also characterized, where analysis provides classification of inhibitor induced shifts away from the semi-open state into weak, moderate and strong effects. The findings are compared to those for prior studies of inhibitor induced conformational shifts in PI-naïve Subtype B, C and CRF_AE.
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Affiliation(s)
- Trang T Tran
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL, 32611, USA
| | - Zhanglong Liu
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL, 32611, USA
| | - Gail E Fanucci
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL, 32611, USA.
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8
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Kneller DW, Agniswamy J, Harrison RW, Weber IT. Highly drug-resistant HIV-1 protease reveals decreased intra-subunit interactions due to clusters of mutations. FEBS J 2020; 287:3235-3254. [PMID: 31920003 PMCID: PMC7343616 DOI: 10.1111/febs.15207] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 11/16/2019] [Accepted: 01/08/2020] [Indexed: 01/07/2023]
Abstract
Drug-resistance is a serious problem for treatment of the HIV/AIDS pandemic. Potent clinical inhibitors of HIV-1 protease show several orders of magnitude worse inhibition of highly drug-resistant variants. Hence, the structure and enzyme activities were analyzed for HIV protease mutant HIV-1 protease (EC 3.4.23.16) (PR) with 22 mutations (PRS5B) from a clinical isolate that was selected by machine learning to represent high-level drug-resistance. PRS5B has 22 mutations including only one (I84V) in the inhibitor binding site; however, clinical inhibitors had poor inhibition of PRS5B activity with kinetic inhibition value (Ki ) values of 4-1000 nm or 18- to 8000-fold worse than for wild-type PR. High-resolution crystal structures of PRS5B complexes with the best inhibitors, amprenavir (APV) and darunavir (DRV) (Ki ~ 4 nm), revealed only minor changes in protease-inhibitor interactions. Instead, two distinct clusters of mutations in distal regions induce coordinated conformational changes that decrease favorable internal interactions across the entire protein subunit. The largest structural rearrangements are described and compared to other characterized resistant mutants. In the protease hinge region, the N83D mutation eliminates a hydrogen bond connecting the hinge and core of the protease and increases disorder compared to highly resistant mutants PR with 17 mutations and PR with 20 mutations with similar hinge mutations. In a distal β-sheet, mutations G73T and A71V coordinate with accessory mutations to bring about shifts that propagate throughout the subunit. Molecular dynamics simulations of ligand-free dimers show differences consistent with loss of interactions in mutant compared to wild-type PR. Clusters of mutations exhibit both coordinated and antagonistic effects, suggesting PRS5B may represent an intermediate stage in the evolution of more highly resistant variants. DATABASES: Structural data are available in Protein Data Bank under the accession codes 6P9A and 6P9B for PRS5B/DRV and PRS5B/APV, respectively.
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Affiliation(s)
- Daniel W. Kneller
- Department of Biology, Georgia State University, Atlanta, Georgia 30303, United States of America
| | - Johnson Agniswamy
- Department of Biology, Georgia State University, Atlanta, Georgia 30303, United States of America
| | - Robert W. Harrison
- Department of Computer Science, Georgia State University, Atlanta, Georgia 30303, United States of America
| | - Irene T. Weber
- Department of Biology, Georgia State University, Atlanta, Georgia 30303, United States of America,Department of Chemistry, Georgia State University, Atlanta, Georgia 30303, United States of America,Author of correspondence:
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9
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Dimer Interface Organization is a Main Determinant of Intermonomeric Interactions and Correlates with Evolutionary Relationships of Retroviral and Retroviral-Like Ddi1 and Ddi2 Proteases. Int J Mol Sci 2020; 21:ijms21041352. [PMID: 32079302 PMCID: PMC7072860 DOI: 10.3390/ijms21041352] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/11/2020] [Accepted: 02/14/2020] [Indexed: 02/07/2023] Open
Abstract
The life cycles of retroviruses rely on the limited proteolysis catalyzed by the viral protease. Numerous eukaryotic organisms also express endogenously such proteases, which originate from retrotransposons or retroviruses, including DNA damage-inducible 1 and 2 (Ddi1 and Ddi2, respectively) proteins. In this study, we performed a comparative analysis based on the structural data currently available in Protein Data Bank (PDB) and Structural summaries of PDB entries (PDBsum) databases, with a special emphasis on the regions involved in dimerization of retroviral and retroviral-like Ddi proteases. In addition to Ddi1 and Ddi2, at least one member of all seven genera of the Retroviridae family was included in this comparison. We found that the studied retroviral and non-viral proteases show differences in the mode of dimerization and density of intermonomeric contacts, and distribution of the structural characteristics is in agreement with their evolutionary relationships. Multiple sequence and structure alignments revealed that the interactions between the subunits depend mainly on the overall organization of the dimer interface. We think that better understanding of the general and specific features of proteases may support the characterization of retroviral-like proteases.
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10
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Kneller DW, Agniswamy J, Ghosh AK, Weber IT. Potent antiviral HIV-1 protease inhibitor combats highly drug resistant mutant PR20. Biochem Biophys Res Commun 2019; 519:61-66. [PMID: 31474336 PMCID: PMC7251940 DOI: 10.1016/j.bbrc.2019.08.126] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 08/23/2019] [Indexed: 01/07/2023]
Abstract
Drug-resistance threatens effective treatment of HIV/AIDS. Clinical inhibitors, including darunavir (1), are ineffective for highly resistant protease mutant PR20, however, antiviral compound 2 derived from 1 with fused tricyclic group at P2, extended amino-benzothiazole P2' ligand and two fluorine atoms on P1 shows 16-fold better inhibition of PR20 enzyme activity. Crystal structures of PR20 and wild-type PR complexes reveal how the extra groups of 2 counteract the expanded ligand-binding pocket, dynamic flaps, and faster dimer dissociation of PR20.
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Affiliation(s)
- Daniel W. Kneller
- Department of Biology, Georgia State University, Atlanta, GA, 30303, USA
| | - Johnson Agniswamy
- Department of Biology, Georgia State University, Atlanta, GA, 30303, USA
| | - Arun K. Ghosh
- Department of Chemistry and Department of Medicinal Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Irene T. Weber
- Department of Biology, Georgia State University, Atlanta, GA, 30303, USA,Department of Chemistry, Georgia State University, Atlanta, GA, 30303, USA,Corresponding author: Phone: (+1) 404-413-5411
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11
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Yoo J, Louis JM, Chung HS. Diverse Folding Pathways of HIV-1 Protease Monomer on a Rugged Energy Landscape. Biophys J 2019; 117:1456-1466. [PMID: 31587829 DOI: 10.1016/j.bpj.2019.09.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 08/27/2019] [Accepted: 09/12/2019] [Indexed: 10/26/2022] Open
Abstract
The modern energy landscape theory of protein folding predicts multiple folding pathways connecting a myriad of unfolded conformations and a well-defined folded state. However, direct experimental observation of heterogeneous folding pathways is difficult. Naturally evolved proteins typically exhibit a smooth folding energy landscape for fast and efficient folding by avoiding unfavorable kinetic traps. In this case, rapid fluctuations between unfolded conformations result in apparent two-state behavior and make different pathways indistinguishable. However, the landscape roughness can be different, depending on the selection pressures during evolution. Here, we characterize the unusually rugged folding energy landscape of human immunodeficiency virus-1 protease monomer using single-molecule Förster resonance energy transfer spectroscopy. Our data show that fluctuations between unfolded conformations are slow, which enables the experimental observation of heterogeneous folding pathways as predicted by the landscape theory. Although the landscape ruggedness is sensitive to the mutations and fluorophore locations, the folding rate is similar for various protease constructs. The natural evolution of the protease to have a rugged energy landscape likely results from intrinsic pressures to maintain robust folding when human immunodeficiency virus-1 mutates frequently, which is essential for its survival.
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Affiliation(s)
- Janghyun Yoo
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - John M Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Hoi Sung Chung
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland.
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12
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Su CTT, Koh DWS, Gan SKE. Reviewing HIV-1 Gag Mutations in Protease Inhibitors Resistance: Insights for Possible Novel Gag Inhibitor Designs. Molecules 2019; 24:molecules24183243. [PMID: 31489889 PMCID: PMC6767625 DOI: 10.3390/molecules24183243] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 09/03/2019] [Accepted: 09/04/2019] [Indexed: 12/31/2022] Open
Abstract
HIV protease inhibitors against the viral protease are often hampered by drug resistance mutations in protease and in the viral substrate Gag. To overcome this drug resistance and inhibit viral maturation, targeting Gag alongside protease rather than targeting protease alone may be more efficient. In order to successfully inhibit Gag, understanding of its drug resistance mutations and the elicited structural changes on protease binding needs to be investigated. While mutations on Gag have already been mapped to protease inhibitor resistance, there remain many mutations, particularly the non-cleavage mutations, that are not characterized. Through structural studies to unravel how Gag mutations contributes to protease drug resistance synergistically, it is thus possible to glean insights to design novel Gag inhibitors. In this review, we discuss the structural role of both novel and previously reported Gag mutations in PI resistance, and how new Gag inhibitors can be designed.
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Affiliation(s)
- Chinh Tran-To Su
- Antibody & Product Development Lab, Bioinformatics Institute, A*STAR, Singapore 138671, Singapore
| | - Darius Wen-Shuo Koh
- Antibody & Product Development Lab, Bioinformatics Institute, A*STAR, Singapore 138671, Singapore
| | - Samuel Ken-En Gan
- Antibody & Product Development Lab, Bioinformatics Institute, A*STAR, Singapore 138671, Singapore.
- p53 Laboratory, A*STAR, Singapore 138648, Singapore.
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13
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Weber IT, Harrison RW. Decoding HIV resistance: from genotype to therapy. Future Med Chem 2017; 9:1529-1538. [PMID: 28791894 PMCID: PMC5694023 DOI: 10.4155/fmc-2017-0048] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 05/03/2017] [Indexed: 01/14/2023] Open
Abstract
Genetic variation in HIV poses a major challenge for prevention and treatment of the AIDS pandemic. Resistance occurs by mutations in the target proteins that lower affinity for the drug or alter the protein dynamics, thereby enabling viral replication in the presence of the drug. Due to the prevalence of drug-resistant strains, monitoring the genotype of the infecting virus is recommended. Computational approaches for predicting resistance from genotype data and guiding therapy are discussed. Many prediction methods rely on rules derived from known resistance-associated mutations, however, statistical or machine learning can improve the classification accuracy and assess unknown mutations. Adding classifiers such as information on the atomic structure of the protein can further enhance the predictions.
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Affiliation(s)
- Irene T Weber
- Department of Biology, Georgia State University, PO Box 4010, Atlanta, GA 30302-4010, USA
| | - Robert W Harrison
- Department of Computer Science, Georgia State University, Atlanta, GA 30303, USA
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14
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Palese LL. Conformations of the HIV-1 protease: A crystal structure data set analysis. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:1416-1422. [PMID: 28846854 DOI: 10.1016/j.bbapap.2017.08.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 07/22/2017] [Accepted: 08/10/2017] [Indexed: 12/25/2022]
Abstract
The HIV protease is an important drug target for HIV/AIDS therapy, and its structure and function have been extensively investigated. This enzyme performs an essential role in viral maturation by processing specific cleavage sites in the Gag and Gag-Pol precursor polyproteins so as to release their mature forms. This 99 amino acid aspartic protease works as a homodimer, with the active site localized in a central cavity capped by two flexible flap regions. The dimer presents closed or open conformations, which are involved in the substrate binding and release. Here the results of the analysis of a HIV-1 protease data set containing 552 dimer structures are reported. Different dimensionality reduction methods have been used in order to get information from this multidimensional database. Most of the structures in the data set belong to two conformational clusters. An interesting observation that comes from the analysis of these data is that some protease sequences are localized preferentially in specific areas of the conformational landscape of this protein.
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Affiliation(s)
- Luigi Leonardo Palese
- University of Bari "Aldo Moro", Department of Basic Medical Sciences, Neurosciences and Sense Organs (SMBNOS), Bari 70124, Italy.
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15
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Gerlits O, Keen DA, Blakeley MP, Louis JM, Weber IT, Kovalevsky A. Room Temperature Neutron Crystallography of Drug Resistant HIV-1 Protease Uncovers Limitations of X-ray Structural Analysis at 100 K. J Med Chem 2017; 60:2018-2025. [PMID: 28195728 DOI: 10.1021/acs.jmedchem.6b01767] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
HIV-1 protease inhibitors are crucial for treatment of HIV-1/AIDS, but their effectiveness is thwarted by rapid emergence of drug resistance. To better understand binding of clinical inhibitors to resistant HIV-1 protease, we used room-temperature joint X-ray/neutron (XN) crystallography to obtain an atomic-resolution structure of the protease triple mutant (V32I/I47V/V82I) in complex with amprenavir. The XN structure reveals a D+ ion located midway between the inner Oδ1 oxygen atoms of the catalytic aspartic acid residues. Comparison of the current XN structure with our previous XN structure of the wild-type HIV-1 protease-amprenavir complex suggests that the three mutations do not significantly alter the drug-enzyme interactions. This is in contrast to the observations in previous 100 K X-ray structures of these complexes that indicated loss of interactions by the drug with the triple mutant protease. These findings, thus, uncover limitations of structural analysis of drug binding using X-ray structures obtained at 100 K.
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Affiliation(s)
- Oksana Gerlits
- UT/ORNL Joint Institute of Biological Sciences, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - David A Keen
- ISIS Facility, Rutherford Appleton Laboratory , Harwell Campus, Didcot, OX11 0QX, U.K
| | - Matthew P Blakeley
- Large-Scale Structures Group, Institut Laue Langevin , 71 avenue des Martyrs, 38000 Grenoble, France
| | - John M Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , DHHS, Bethesda, Maryland 20892-0520, United States
| | - Irene T Weber
- Departments of Chemistry and Biology, Georgia State University , Atlanta, Georgia 30302, United States
| | - Andrey Kovalevsky
- Biology and Soft Matter Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
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17
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Su CTT, Ling WL, Lua WH, Haw YX, Gan SKE. Structural analyses of 2015-updated drug-resistant mutations in HIV-1 protease: an implication of protease inhibitor cross-resistance. BMC Bioinformatics 2016; 17:500. [PMID: 28155724 PMCID: PMC5259968 DOI: 10.1186/s12859-016-1372-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Background Strategies to control HIV for improving the quality of patient lives have been aided by the Highly Active Anti-Retroviral Therapy (HAART), which consists of a cocktail of inhibitors targeting key viral enzymes. Numerous new drugs have been developed over the past few decades but viral resistances to these drugs in the targeted viral enzymes are increasingly reported. Nonetheless the acquired mutations often reduce viral fitness and infectivity. Viral compensatory secondary-line mutations mitigate this loss of fitness, equipping the virus with a broad spectrum of resistance against these drugs. While structural understanding of the viral protease and its drug resistance mutations have been well established, the interconnectivity and development of structural cross-resistance remain unclear. This paper reports the structural analyses of recent clinical mutations on the drug cross-resistance effects from various protease and protease inhibitors (PIs) complexes. Methods Using the 2015 updated clinical HIV protease mutations, we constructed a structure-based correlation network and a minimum-spanning tree (MST) based on the following features: (i) topology of the PI-binding pocket, (ii) allosteric effects of the mutations, and (iii) protease structural stability. Results and conclusion Analyis of the network and the MST of dominant mutations conferring resistance to the seven PIs (Atazanavir-ATV, Darunavir-DRV, Indinavir-IDV, Lopinavir-LPV, Nelfinavir-NFV, Saquinavir-SQV, and Tipranavir-TPV) showed that cross-resistance can develop easily across NFV, SQV, LPV, IDV, and DRV, but not for ATV or TPV. Through estimation of the changes in vibrational entropies caused by each reported mutation, some secondary mutations were found to destabilize protease structure. Our findings provide an insight into the mechanism of PI cross-resistance and may also be useful in guiding the selection of PI in clinical treatment to delay the onset of cross drug resistance. Electronic supplementary material The online version of this article (doi:10.1186/s12859-016-1372-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Chinh Tran-To Su
- Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR), Singapore, 138671, Singapore.
| | - Wei-Li Ling
- Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR), Singapore, 138671, Singapore
| | - Wai-Heng Lua
- Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR), Singapore, 138671, Singapore
| | - Yu-Xuan Haw
- Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR), Singapore, 138671, Singapore
| | - Samuel Ken-En Gan
- Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR), Singapore, 138671, Singapore. .,p53 Laboratory, Agency for Science, Technology, and Research (A*STAR), Singapore, 138648, Singapore.
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Agniswamy J, Louis JM, Roche J, Harrison RW, Weber IT. Structural Studies of a Rationally Selected Multi-Drug Resistant HIV-1 Protease Reveal Synergistic Effect of Distal Mutations on Flap Dynamics. PLoS One 2016; 11:e0168616. [PMID: 27992544 PMCID: PMC5161481 DOI: 10.1371/journal.pone.0168616] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 12/02/2016] [Indexed: 12/20/2022] Open
Abstract
We report structural analysis of HIV protease variant PRS17 which was rationally selected by machine learning to represent wide classes of highly drug-resistant variants. Crystal structures were solved of PRS17 in the inhibitor-free form and in complex with antiviral inhibitor, darunavir. Despite its 17 mutations, PRS17 has only one mutation (V82S) in the inhibitor/substrate binding cavity, yet exhibits high resistance to all clinical inhibitors. PRS17 has none of the major mutations (I47V, I50V, I54ML, L76V and I84V) associated with darunavir resistance, but has 10,000-fold weaker binding affinity relative to the wild type PR. Comparable binding affinity of 8000-fold weaker than PR is seen for drug resistant mutant PR20, which bears 3 mutations associated with major resistance to darunavir (I47V, I54L and I84V). Inhibitor-free PRS17 shows an open flap conformation with a curled tip correlating with G48V flap mutation. NMR studies on inactive PRS17D25N unambiguously confirm that the flaps adopt mainly an open conformation in solution very similar to that in the inhibitor-free crystal structure. In PRS17, the hinge loop cluster of mutations, E35D, M36I and S37D, contributes to the altered flap dynamics by a mechanism similar to that of PR20. An additional K20R mutation anchors an altered conformation of the hinge loop. Flap mutations M46L and G48V in PRS17/DRV complex alter the Phe53 conformation by steric hindrance between the side chains. Unlike the L10F mutation in PR20, L10I in PRS17 does not break the inter-subunit ion pair or diminish the dimer stability, consistent with a very low dimer dissociation constant comparable to that of wild type PR. Distal mutations A71V, L90M and I93L propagate alterations to the catalytic site of PRS17. PRS17 exhibits a molecular mechanism whereby mutations act synergistically to alter the flap dynamics resulting in significantly weaker binding yet maintaining active site contacts with darunavir.
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Affiliation(s)
- Johnson Agniswamy
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
| | - John M. Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, DHHS, Bethesda, Maryland, United States of America
| | - Julien Roche
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, DHHS, Bethesda, Maryland, United States of America
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa, United States of America
| | - Robert W. Harrison
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
- Department of Computer Science, Georgia State University, Atlanta, Georgia, United States of America
| | - Irene T. Weber
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
- Department of Chemistry, Georgia State University, Atlanta, Georgia, United States of America
- * E-mail:
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Liu Z, Huang X, Hu L, Pham L, Poole KM, Tang Y, Mahon BP, Tang W, Li K, Goldfarb NE, Dunn BM, McKenna R, Fanucci GE. Effects of Hinge-region Natural Polymorphisms on Human Immunodeficiency Virus-Type 1 Protease Structure, Dynamics, and Drug Pressure Evolution. J Biol Chem 2016; 291:22741-22756. [PMID: 27576689 DOI: 10.1074/jbc.m116.747568] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 08/30/2016] [Indexed: 11/06/2022] Open
Abstract
Multidrug resistance to current Food and Drug Administration-approved HIV-1 protease (PR) inhibitors drives the need to understand the fundamental mechanisms of how drug pressure-selected mutations, which are oftentimes natural polymorphisms, elicit their effect on enzyme function and resistance. Here, the impacts of the hinge-region natural polymorphism at residue 35, glutamate to aspartate (E35D), alone and in conjunction with residue 57, arginine to lysine (R57K), are characterized with the goal of understanding how altered salt bridge interactions between the hinge and flap regions are associated with changes in structure, motional dynamics, conformational sampling, kinetic parameters, and inhibitor affinity. The combined results reveal that the single E35D substitution leads to diminished salt bridge interactions between residues 35 and 57 and gives rise to the stabilization of open-like conformational states with overall increased backbone dynamics. In HIV-1 PR constructs where sites 35 and 57 are both mutated (e.g. E35D and R57K), x-ray structures reveal an altered network of interactions that replace the salt bridge thus stabilizing the structural integrity between the flap and hinge regions. Despite the altered conformational sampling and dynamics when the salt bridge is disrupted, enzyme kinetic parameters and inhibition constants are similar to those obtained for subtype B PR. Results demonstrate that these hinge-region natural polymorphisms, which may arise as drug pressure secondary mutations, alter protein dynamics and the conformational landscape, which are important thermodynamic parameters to consider for development of inhibitors that target for non-subtype B PR.
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Affiliation(s)
- Zhanglong Liu
- From the Department of Chemistry, University of Florida, Gainesville, Florida 32611 and
| | - Xi Huang
- From the Department of Chemistry, University of Florida, Gainesville, Florida 32611 and
| | - Lingna Hu
- From the Department of Chemistry, University of Florida, Gainesville, Florida 32611 and
| | - Linh Pham
- From the Department of Chemistry, University of Florida, Gainesville, Florida 32611 and
| | - Katye M Poole
- the Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610
| | - Yan Tang
- the Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610
| | - Brian P Mahon
- the Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610
| | - Wenxing Tang
- the Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610
| | - Kunhua Li
- From the Department of Chemistry, University of Florida, Gainesville, Florida 32611 and
| | - Nathan E Goldfarb
- the Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610
| | - Ben M Dunn
- the Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610
| | - Robert McKenna
- the Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610
| | - Gail E Fanucci
- From the Department of Chemistry, University of Florida, Gainesville, Florida 32611 and
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Louis JM, Roche J. Evolution under Drug Pressure Remodels the Folding Free-Energy Landscape of Mature HIV-1 Protease. J Mol Biol 2016; 428:2780-92. [PMID: 27170547 PMCID: PMC4905781 DOI: 10.1016/j.jmb.2016.05.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/27/2016] [Accepted: 05/02/2016] [Indexed: 01/08/2023]
Abstract
Using high-pressure NMR spectroscopy and differential scanning calorimetry, we investigate the folding landscape of the mature HIV-1 protease homodimer. The cooperativity of unfolding was measured in the absence or presence of a symmetric active site inhibitor for the optimized wild type protease (PR), its inactive variant PRD25N, and an extremely multidrug-resistant mutant, PR20. The individual fit of the pressure denaturation profiles gives rise to first order, ∆GNMR, and second order, ∆VNMR (the derivative of ∆GNMR with pressure); apparent thermodynamic parameters for each amide proton considered. Heterogeneity in the apparent ∆VNMR values reflects departure from an ideal cooperative unfolding transition. The narrow to broad distribution of ∆VNMR spanning the extremes from inhibitor-free PR20D25N to PR-DMP323 complex, and distinctively for PRD25N-DMP323 complex, indicated large variations in folding cooperativity. Consistent with this data, the shape of thermal unfolding transitions varies from asymmetric for PR to nearly symmetric for PR20, as dimer-inhibitor ternary complexes. Lack of structural cooperativity was observed between regions located close to the active site, including the hinge and tip of the glycine-rich flaps, and the rest of the protein. These results strongly suggest that inhibitor binding drastically decreases the cooperativity of unfolding by trapping the closed flap conformation in a deep energy minimum. To evade this conformational trap, PR20 evolves exhibiting a smoother folding landscape with nearly an ideal two-state (cooperative) unfolding transition. This study highlights the malleability of retroviral protease folding pathways by illustrating how the selection of mutations under drug pressure remodels the free-energy landscape as a primary mechanism.
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Affiliation(s)
- John M Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Julien Roche
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA.
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21
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Mahanti M, Bhakat S, Nilsson UJ, Söderhjelm P. Flap Dynamics in Aspartic Proteases: A Computational Perspective. Chem Biol Drug Des 2016; 88:159-77. [PMID: 26872937 DOI: 10.1111/cbdd.12745] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recent advances in biochemistry and drug design have placed proteases as one of the critical target groups for developing novel small-molecule inhibitors. Among all proteases, aspartic proteases have gained significant attention due to their role in HIV/AIDS, malaria, Alzheimer's disease, etc. The binding cleft is covered by one or two β-hairpins (flaps) which need to be opened before a ligand can bind. After binding, the flaps close to retain the ligand in the active site. Development of computational tools has improved our understanding of flap dynamics and its role in ligand recognition. In the past decade, several computational approaches, for example molecular dynamics (MD) simulations, coarse-grained simulations, replica-exchange molecular dynamics (REMD) and metadynamics, have been used to understand flap dynamics and conformational motions associated with flap movements. This review is intended to summarize the computational progress towards understanding the flap dynamics of proteases and to be a reference for future studies in this field.
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Affiliation(s)
- Mukul Mahanti
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, PO Box 124, SE-221 00, Lund, Sweden
| | - Soumendranath Bhakat
- Division of Biophysical Chemistry, Department of Chemistry, Lund University, PO Box 124, SE-22100, Lund, Sweden
| | - Ulf J Nilsson
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, PO Box 124, SE-221 00, Lund, Sweden
| | - Pär Söderhjelm
- Division of Biophysical Chemistry, Department of Chemistry, Lund University, PO Box 124, SE-22100, Lund, Sweden
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