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Tabler CO, Wegman SJ, Alhusaini N, Lee NF, Tilton JC. Premature Activation of the HIV-1 Protease Is Influenced by Polymorphisms in the Hinge Region. Viruses 2024; 16:849. [PMID: 38932142 PMCID: PMC11209583 DOI: 10.3390/v16060849] [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: 04/30/2024] [Revised: 05/21/2024] [Accepted: 05/24/2024] [Indexed: 06/28/2024] Open
Abstract
HIV-1 protease inhibitors are an essential component of antiretroviral therapy. However, drug resistance is a pervasive issue motivating a persistent search for novel therapies. Recent reports found that when protease activates within the host cell's cytosol, it facilitates the pyroptotic killing of infected cells. This has led to speculation that promoting protease activation, rather than inhibiting it, could help to eradicate infected cells and potentially cure HIV-1 infection. Here, we used a nanoscale flow cytometry-based assay to characterize protease resistance mutations and polymorphisms. We quantified protease activity, viral concentration, and premature protease activation and confirmed previous findings that major resistance mutations generally destabilize the protease structure. Intriguingly, we found evidence that common polymorphisms in the hinge domain of protease can influence its susceptibility to premature activation. This suggests that viral heterogeneity could pose a considerable challenge for therapeutic strategies aimed at inducing premature protease activation in the future.
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Affiliation(s)
| | | | | | | | - John C. Tilton
- Center for Proteomics and Bioinformatics, Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA; (C.O.T.); (N.A.)
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2
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Hisamuddin M, Rizvi I, Malik A, Nabi F, Hassan MN, Ali SM, Khan JM, Khan TH, Khan RH. Characterization of pH-induced conformational changes in recombinant DENV NS2B-NS3pro. Int J Biol Macromol 2023; 253:126823. [PMID: 37703975 DOI: 10.1016/j.ijbiomac.2023.126823] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 09/07/2023] [Accepted: 09/07/2023] [Indexed: 09/15/2023]
Abstract
The increasing frequency of Dengue is a cause of severe epidemics and therefore demands strategies for effective prevention, diagnosis, and treatment. DENV-protease is being investigated as a potential therapeutic target. However, due to the flat and highly charged active site of the DENV-protease, designing orthosteric medicines is very difficult. In this study, we have done a thorough analysis of pH-dependent conformational changes in recombinantly expressed DENV protease using various spectroscopic techniques. Our spectroscopic study of DENV protease (NS2B-NS3pro) at different pH conditions gives important insights into the dynamicity of structural conformation. At physiological pH, the DENV-protease exists in a random-coiled state. Lowering the pH promotes the formation of alpha-helical and beta-sheet structures i.e. gain of secondary structure as shown by Far-UV CD. The light scattering and Thioflavin T (ThT)-binding assay proved the aggregation-prone tendency of DENV-protease at pH 4.0. Further, the confocal microscopy image intensity showed the amorphous aggregate formation of DENV protease at pH 4.0. Thus, the DENV protease acquires different conformations with changes in pH conditions. Together, these results have the potential to facilitate the design of a conformation destabilizer-based therapeutic strategy for dengue fever.
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Affiliation(s)
- Malik Hisamuddin
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University Aligarh, UP, India
| | - Irum Rizvi
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University Aligarh, UP, India
| | - Ajamaluddin Malik
- Department of Biochemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh, Saudi Arabia
| | - Faisal Nabi
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University Aligarh, UP, India
| | - Md Nadir Hassan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University Aligarh, UP, India
| | - Syed Moasfar Ali
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University Aligarh, UP, India
| | - Javed Masood Khan
- Department of Food Science and Nutrition, Faculty of Food and Agricultural Sciences, King Saud University, 2460, Riyadh 11451, Saudi Arabia
| | - Tabish H Khan
- Department of Pathology and Immunology, Washington University in St. Louis School of Medicine, MO, USA
| | - Rizwan H Khan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University Aligarh, UP, India.
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3
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Petri YD, Gutierrez CS, Raines RT. Chemoselective Caging of Carboxyl Groups for On-Demand Protein Activation with Small Molecules. Angew Chem Int Ed Engl 2023; 62:e202215614. [PMID: 36964973 PMCID: PMC10243506 DOI: 10.1002/anie.202215614] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 03/02/2023] [Accepted: 03/24/2023] [Indexed: 03/27/2023]
Abstract
Tools for on-demand protein activation enable impactful gain-of-function studies in biological settings. Thus far, however, proteins have been chemically caged at primarily Lys, Tyr, and Sec, typically through the genetic encoding of unnatural amino acids. Herein, we report that the preferential reactivity of diazo compounds with protonated acids can be used to expand this toolbox to solvent-accessible carboxyl groups with an elevated pKa value. As a model protein, we employed lysozyme (Lyz), which has an active-site Glu35 residue with a pKa value of 6.2. A diazo compound with a bioorthogonal self-immolative handle esterified Glu35 selectively, inactivating Lyz. The hydrolytic activity of the caged Lyz on bacterial cell walls was restored with two small-molecule triggers. The decaging was more efficient by small molecules than by esterases. This simple chemical strategy was also applied to a hemeprotein and an aspartyl protease, setting the stage for broad applicability.
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Affiliation(s)
- Yana D. Petri
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307, USA
| | - Clair S. Gutierrez
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307, USA
| | - Ronald T. Raines
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307, USA
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4
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Sherry D, Pandian R, Sayed Y. Non-active site mutations in the HIV protease: Diminished drug binding affinity is achieved through modulating the hydrophobic sliding mechanism. Int J Biol Macromol 2022; 217:27-41. [PMID: 35817239 DOI: 10.1016/j.ijbiomac.2022.07.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 06/17/2022] [Accepted: 07/05/2022] [Indexed: 11/27/2022]
Abstract
The global HIV/AIDS epidemic still currently affects approximately 38 million individuals globally. The protease enzyme of the human immunodeficiency virus is a major drug target in antiviral therapy, however, under the influence of reverse transcriptase and in the context of drug pressure, the rapid PR mutation rate contributes significantly to clinical failure. The set of cooperative non-active site mutations, I13V/I62V/V77I, have been associated with reduced inhibitor susceptibility and are the focus of the current study. When compared to the wild-type protease the mutant protease exhibited decreased binding affinities towards ATV and DRV by 64- and 12-fold, respectively, and decreased the overall favourable Gibbs free energy for ATV, DRV, RTV and SQV. Moreover, these mutations decreased the thermal stability of the protease when in complex with ATV and DRV by approximately 6.4 and 4.2 °C, respectively. The crystal structure of the mutant protease revealed that the location of these mutations and their effect on the hydrophobic sliding mechanism may be crucial in their role in resistance.
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Affiliation(s)
- Dean Sherry
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050, South Africa
| | - Ramesh Pandian
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050, South Africa
| | - Yasien Sayed
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050, South Africa.
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5
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Nashed NT, Aniana A, Ghirlando R, Chiliveri SC, Louis JM. Modulation of the monomer-dimer equilibrium and catalytic activity of SARS-CoV-2 main protease by a transition-state analog inhibitor. Commun Biol 2022; 5:160. [PMID: 35233052 PMCID: PMC8888643 DOI: 10.1038/s42003-022-03084-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 01/28/2022] [Indexed: 12/17/2022] Open
Abstract
The role of dimer formation for the onset of catalytic activity of SARS-CoV-2 main protease (MProWT) was assessed using a predominantly monomeric mutant (MProM). Rates of MProWT and MProM catalyzed hydrolyses display substrate saturation kinetics and second-order dependency on the protein concentration. The addition of the prodrug GC376, an inhibitor of MProWT, to MProM leads to an increase in the dimer population and catalytic activity with increasing inhibitor concentration. The activity reaches a maximum corresponding to a dimer population in which one active site is occupied by the inhibitor and the other is available for catalytic activity. This phase is followed by a decrease in catalytic activity due to the inhibitor competing with the substrate. Detailed kinetics and equilibrium analyses are presented and a modified Michaelis-Menten equation accounts for the results. These observations provide conclusive evidence that dimer formation is coupled to catalytic activity represented by two equivalent active sites.
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Affiliation(s)
- Nashaat T Nashed
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Annie Aniana
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Rodolfo Ghirlando
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Sai Chaitanya Chiliveri
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - John M Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
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6
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Ramlucken U, Babu Naidu KS, Govender P. Improved Production of HIV-1 Subtype C Protease from Transgenic E. Coli. Open Microbiol J 2021. [DOI: 10.2174/1874285802115010168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Background:
Human Immunodeficiency Virus 1 (HIV-1) subtype C is responsible for the majority of infections of patients in Southern Africa. The HIV protease is a primary target for the development of highly efficient anti-retroviral pharmaceuticals because of its pivotal role in the maturation of the virus in the host cell. For target validation of novel HIV protease inhibitors, there is a need for the availability of an abundance of this protease.
Objective:
This study reports an optimized method to produce HIV-1 protease derived from HIV-1 subtype C.
Methods:
It involves the use of a transgenic E. coli strain that overexpresses the native form of the enzyme via inclusion bodies. A stringent method for the isolation, purification, and renaturation resulted in the production of highly pure active HIV-1 protease. In order to facilitate an increase in protease yields, an optimized growth strategy was developed. In this regard, a chemically defined medium with lower glucose content and devoid of essential amino acids of the TCA cycle was used as an alternative to the widely used nutrient-rich Luria Bertani (LB) medium.
Results:
Results indicated an increase in protease yield up to twice the amount, thereby making this medium an attractive alternative for increasing biomass and HIV protease production for future research.
Conclusion:
An optimized method for HIV-1 protease derived from HIV-1 subtype C production using chemically defined media was established. This was achieved using a known method to isolate and purify the enzyme with the use of a specialized feeding strategy.
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7
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Lyonnais S, Sadiq SK, Lorca-Oró C, Dufau L, Nieto-Marquez S, Escribà T, Gabrielli N, Tan X, Ouizougun-Oubari M, Okoronkwo J, Reboud-Ravaux M, Gatell JM, Marquet R, Paillart JC, Meyerhans A, Tisné C, Gorelick RJ, Mirambeau G. The HIV-1 Nucleocapsid Regulates Its Own Condensation by Phase-Separated Activity-Enhancing Sequestration of the Viral Protease during Maturation. Viruses 2021; 13:v13112312. [PMID: 34835118 PMCID: PMC8625067 DOI: 10.3390/v13112312] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/09/2021] [Accepted: 11/11/2021] [Indexed: 02/07/2023] Open
Abstract
A growing number of studies indicate that mRNAs and long ncRNAs can affect protein populations by assembling dynamic ribonucleoprotein (RNP) granules. These phase-separated molecular ‘sponges’, stabilized by quinary (transient and weak) interactions, control proteins involved in numerous biological functions. Retroviruses such as HIV-1 form by self-assembly when their genomic RNA (gRNA) traps Gag and GagPol polyprotein precursors. Infectivity requires extracellular budding of the particle followed by maturation, an ordered processing of ∼2400 Gag and ∼120 GagPol by the viral protease (PR). This leads to a condensed gRNA-NCp7 nucleocapsid and a CAp24-self-assembled capsid surrounding the RNP. The choreography by which all of these components dynamically interact during virus maturation is one of the missing milestones to fully depict the HIV life cycle. Here, we describe how HIV-1 has evolved a dynamic RNP granule with successive weak–strong–moderate quinary NC-gRNA networks during the sequential processing of the GagNC domain. We also reveal two palindromic RNA-binding triads on NC, KxxFxxQ and QxxFxxK, that provide quinary NC-gRNA interactions. Consequently, the nucleocapsid complex appears properly aggregated for capsid reassembly and reverse transcription, mandatory processes for viral infectivity. We show that PR is sequestered within this RNP and drives its maturation/condensation within minutes, this process being most effective at the end of budding. We anticipate such findings will stimulate further investigations of quinary interactions and emergent mechanisms in crowded environments throughout the wide and growing array of RNP granules.
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Affiliation(s)
- Sébastien Lyonnais
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
- Centre d’Etudes des Maladies Infectieuses et Pharmacologie Anti-Infectieuse (CEMIPAI), CNRS UAR 3725, Université de Montpellier, 1919 Route de Mende, CEDEX 05, 34293 Montpellier, France
- Correspondence: (S.L.); (S.K.S.); (G.M.)
| | - S. Kashif Sadiq
- Infection Biology Laboratory, Department of Experimental and Health Sciences (DCEXS), Universitat Pompeu Fabra, Carrer Doctor Aiguader 88, 08003 Barcelona, Spain;
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany
- Genome Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
- Correspondence: (S.L.); (S.K.S.); (G.M.)
| | - Cristina Lorca-Oró
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
| | - Laure Dufau
- Biological Adaptation and Ageing (B2A), CNRS UMR 8256 & INSERM ERL U1164, Institut de Biologie Paris-Seine (IBPS), Faculté des Sciences et d’Ingénierie (FSI), Sorbonne Université, 7 Quai St Bernard, CEDEX 05, 75252 Paris, France; (L.D.); (M.R.-R.)
| | - Sara Nieto-Marquez
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
| | - Tuixent Escribà
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
| | - Natalia Gabrielli
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
| | - Xiao Tan
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
- Biological Adaptation and Ageing (B2A), CNRS UMR 8256 & INSERM ERL U1164, Institut de Biologie Paris-Seine (IBPS), Faculté des Sciences et d’Ingénierie (FSI), Sorbonne Université, 7 Quai St Bernard, CEDEX 05, 75252 Paris, France; (L.D.); (M.R.-R.)
| | - Mohamed Ouizougun-Oubari
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
| | - Josephine Okoronkwo
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
| | - Michèle Reboud-Ravaux
- Biological Adaptation and Ageing (B2A), CNRS UMR 8256 & INSERM ERL U1164, Institut de Biologie Paris-Seine (IBPS), Faculté des Sciences et d’Ingénierie (FSI), Sorbonne Université, 7 Quai St Bernard, CEDEX 05, 75252 Paris, France; (L.D.); (M.R.-R.)
| | - José Maria Gatell
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
- Facultat de Medicina y Ciencias de la Salud, Universitat de Barcelona, Carrer de Casanova 143, 08036 Barcelona, Spain
| | - Roland Marquet
- Architecture et Réactivité de l’ARN, CNRS UPR 9002, Université de Strasbourg, 2 Allée Conrad Roentgen, 67000 Strasbourg, France; (R.M.); (J.-C.P.)
| | - Jean-Christophe Paillart
- Architecture et Réactivité de l’ARN, CNRS UPR 9002, Université de Strasbourg, 2 Allée Conrad Roentgen, 67000 Strasbourg, France; (R.M.); (J.-C.P.)
| | - Andreas Meyerhans
- Infection Biology Laboratory, Department of Experimental and Health Sciences (DCEXS), Universitat Pompeu Fabra, Carrer Doctor Aiguader 88, 08003 Barcelona, Spain;
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig de Lluís Companys 23, 08010 Barcelona, Spain
| | - Carine Tisné
- Expression Génétique Microbienne, CNRS UMR 8261, Institut de Biologie Physico-Chimique (IBPC), Université de Paris, 13 Rue Pierre et Marie Curie, 75005 Paris, France;
| | - Robert J. Gorelick
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21701, USA;
| | - Gilles Mirambeau
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
- Biologie Intégrative des Organismes Marins (BIOM), CNRS UMR 7232, Observatoire Océanologique de Banyuls (OOB), Faculté des Sciences et d’Ingénierie (FSI), Sorbonne Université, 1 Avenue Pierre Fabre, 66650 Banyuls-sur-Mer, France
- Correspondence: (S.L.); (S.K.S.); (G.M.)
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8
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Sherry D, Worth R, Sayed Y. Elasticity-Associated Functionality and Inhibition of the HIV Protease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1371:79-108. [PMID: 34351572 DOI: 10.1007/5584_2021_655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
HIV protease plays a critical role in the life cycle of the virus through the generation of mature and infectious virions. Detailed knowledge of the structure of the enzyme and its substrate has led to the development of protease inhibitors. However, the development of resistance to all currently available protease inhibitors has contributed greatly to the decreased success of antiretroviral therapy. When therapy failure occurs, multiple mutations are found within the protease sequence starting with primary mutations, which directly impact inhibitor binding, which can also negatively impact viral fitness and replicative capacity by decreasing the binding affinity of the natural substrates to the protease. As such, secondary mutations which are located outside of the active site region accumulate to compensate for the recurrently deleterious effects of primary mutations. However, the resistance mechanism of these secondary mutations is not well understood, but what is known is that these secondary mutations contribute to resistance in one of two ways, either through increasing the energetic penalty associated with bringing the protease into the closed conformation, or, through decreasing the stability of the protein/drug complex in a manner that increases the dissociation rate of the drug, leading to diminished inhibition. As a result, the elasticity of the enzyme-substrate complex has been implicated in the successful recognition and catalysis of the substrates which may be inferred to suggest that the elasticity of the enzyme/drug complex plays a role in resistance. A realistic representation of the dynamic nature of the protease may provide a more powerful tool in structure-based drug design algorithms.
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Affiliation(s)
- Dean Sherry
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, South Africa
| | - Roland Worth
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, South Africa
| | - Yasien Sayed
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, South Africa.
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9
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Ota R, So K, Tsuda M, Higuchi Y, Yamashita F. Prediction of HIV drug resistance based on the 3D protein structure: Proposal of molecular field mapping. PLoS One 2021; 16:e0255693. [PMID: 34347839 PMCID: PMC8336827 DOI: 10.1371/journal.pone.0255693] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 07/21/2021] [Indexed: 11/19/2022] Open
Abstract
A method for predicting HIV drug resistance by using genotypes would greatly assist in selecting appropriate combinations of antiviral drugs. Models reported previously have had two major problems: lack of information on the 3D protein structure and processing of incomplete sequencing data in the modeling procedure. We propose obtaining the 3D structural information of viral proteins by using homology modeling and molecular field mapping, instead of just their primary amino acid sequences. The molecular field potential parameters reflect the physicochemical characteristics associated with the 3D structure of the proteins. We also introduce the Bayesian conditional mutual information theory to estimate the probabilities of occurrence of all possible protein candidates from an incomplete sequencing sample. This approach allows for the effective use of uncertain information for the modeling process. We applied these data analysis techniques to the HIV-1 protease inhibitor dataset and developed drug resistance prediction models with reasonable performance.
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Affiliation(s)
- Ryosaku Ota
- Department of Drug Delivery Research, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Kanako So
- Department of Applied Pharmaceutics and Pharmacokinetics, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Masahiro Tsuda
- Department of Applied Pharmaceutics and Pharmacokinetics, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Yuriko Higuchi
- Department of Drug Delivery Research, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Fumiyoshi Yamashita
- Department of Drug Delivery Research, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
- Department of Applied Pharmaceutics and Pharmacokinetics, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
- * E-mail:
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10
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Rösner HI, Caldarini M, Potel G, Malmodin D, Vanoni MA, Aliverti A, Broglia RA, Kragelund BB, Tiana G. The denatured state of HIV-1 protease under native conditions. Proteins 2021; 90:96-109. [PMID: 34312913 PMCID: PMC9290662 DOI: 10.1002/prot.26189] [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: 06/10/2021] [Revised: 07/21/2021] [Accepted: 07/22/2021] [Indexed: 12/01/2022]
Abstract
The denatured state of several proteins has been shown to display transient structures that are relevant for folding, stability, and aggregation. To detect them by nuclear magnetic resonance (NMR) spectroscopy, the denatured state must be stabilized by chemical agents or changes in temperature. This makes the environment different from that experienced in biologically relevant processes. Using high‐resolution heteronuclear NMR spectroscopy, we have characterized several denatured states of a monomeric variant of HIV‐1 protease, which is natively structured in water, induced by different concentrations of urea, guanidinium chloride, and acetic acid. We have extrapolated the chemical shifts and the relaxation parameters to the denaturant‐free denatured state at native conditions, showing that they converge to the same values. Subsequently, we characterized the conformational properties of this biologically relevant denatured state under native conditions by advanced molecular dynamics simulations and validated the results by comparison to experimental data. We show that the denatured state of HIV‐1 protease under native conditions displays rich patterns of transient native and non‐native structures, which could be of relevance to its guidance through a complex folding process.
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Affiliation(s)
- Heike I Rösner
- BRIC, University of Copenhagen, Copenhagen N, Denmark.,Structural Biology and NMR Laboratory (SBiNlab), Department of Biology, University of Copenhagen, Copenhagen N, Denmark
| | - Martina Caldarini
- Department of Physics, Università degli Studi di Milano and INFN, Milan, Italy
| | - Gregory Potel
- Lawrence Livermore National Laboratory, Livermore, California, USA
| | - Daniel Malmodin
- Structural Biology and NMR Laboratory (SBiNlab), Department of Biology, University of Copenhagen, Copenhagen N, Denmark
| | - Maria A Vanoni
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | | | - Ricardo A Broglia
- Department of Physics, Università degli Studi di Milano and INFN, Milan, Italy.,Niels Bohr Institutet, University of Copenhagen, Copenhagen Ø, Denmark
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory (SBiNlab), Department of Biology, University of Copenhagen, Copenhagen N, Denmark
| | - Guido Tiana
- Department of Physics, Università degli Studi di Milano and INFN, Milan, Italy.,Center for Complexity and Biosystems, Università degli Studi di Milano, Milan, Italy
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11
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Kumar A, Kumar P, Aarthy M, Singh SK, Giri R. Experiments and simulation on ZIKV NS2B-NS3 protease reveal its complex folding. Virology 2021; 556:110-123. [PMID: 33561698 DOI: 10.1016/j.virol.2021.01.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 11/29/2020] [Accepted: 01/21/2021] [Indexed: 11/18/2022]
Abstract
Zika virus has been identified in various body fluids such as semen, urine, saliva, cerebrospinal fluid, and vaginal secretion of an infected individual. The pH of these fluids varies from mildly acidic to mildly alkaline. So it is imperative to understand the impact of these conditions on viral protein functioning. We investigated the NS2B-NS3 protease stability and its activity in different denaturing environments. Finding indicates that NS2B-NS3 protease maintains stability at pH 4.8-8.7. Thus it suggests that the complex remains functionally active to hydrolyze the polyprotein within a diverse environmental condition such as variable pH. Despite a stable structure at a broad pH range, a change in environmental conditions dramatically influence its protease activity. Moreover, it is susceptible to structural transformation leading to increased β-strand or helix content in the presence of alcohol. This study may help further to understand the folding-function relationship of the general flaviviral protease complex.
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Affiliation(s)
- Ankur Kumar
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, 175005, Himachal Pradesh, India
| | - Prateek Kumar
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, 175005, Himachal Pradesh, India
| | - Murali Aarthy
- Department of Bioinformatics, Computer Aided Drug Design and Molecular Modeling Laboratory, Alagappa University, Science Block, Karaikudi, 630003, Tamil Nadu, India
| | - Sanjeev Kumar Singh
- Department of Bioinformatics, Computer Aided Drug Design and Molecular Modeling Laboratory, Alagappa University, Science Block, Karaikudi, 630003, Tamil Nadu, India
| | - Rajanish Giri
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, 175005, Himachal Pradesh, India.
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12
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Chiang M, Wang C. A Single Amino Acid Substitution at the HIV-1 Protease Termini Dimer Interface Significantly Reduces Viral Particles Processing Efficiency. Jpn J Infect Dis 2020; 74:299-306. [PMID: 33390426 DOI: 10.7883/yoken.jjid.2020.286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The dimeric form of HIV-1 protease (PR) is required for its full proteolytic activity. The stability of the dimer primarily depends on the termini interface, with N-terminal residues 1-4 of one monomer encountering C-terminal residues 96-99 of another. We made an alanine substitution for valine 3 (V3) or leucine 97 (L97) at the termini dimer interface and tested their proteolytic activity. We found that an alanine substitution for L97 (PRL97A) completely inhibited the proteolytic activity of the PR. However, an alanine substitution for V3 (PRV3A) partially impaired the proteolytic activity. We then introduced two forced-dimerization systems involving nucleocapsid (NC) replacement or the addition of 1-2 leucine zippers to determine whether the proteolytic activity of dimer-defective PRs could be restored. We found that two forced-dimerization systems compensated for the defect in PRV3A, but not in PRL97A. This implies that PRV3A and PRL97A potentially impair the PR via different mechanisms or cause defects in PR activity to different extents. These novel findings will likely serve as a foundation for developing new PR inhibitors for treating drug-resistant HIV-1 infections in the future.
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Affiliation(s)
- Meichun Chiang
- Division of Preventive Medicine, Institute of Public Health, School of Medicine, National Yang-Ming University, Taiwan
| | - Chintien Wang
- Institute of Clinical Medicine, National Yang-Ming University, Taiwan.,Department of Medical Research, Taipei Veterans General Hospital, Taiwan
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13
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Khan SN, Persons JD, Guerrero M, Ilina TV, Oda M, Ishima R. A synergy of activity, stability, and inhibitor-interaction of HIV-1 protease mutants evolved under drug-pressure. Protein Sci 2020; 30:571-582. [PMID: 33314454 DOI: 10.1002/pro.4013] [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: 10/16/2020] [Revised: 12/04/2020] [Accepted: 12/06/2020] [Indexed: 01/01/2023]
Abstract
A clinically-relevant, drug-resistant mutant of HIV-1 protease (PR), termed Flap+(I54V) and containing L10I, G48V, I54V and V82A mutations, is known to produce significant changes in the entropy and enthalpy balance of drug-PR interactions, compared to wild-type PR. A similar mutant, Flap+(I54A) , which evolves from Flap+(I54V) and contains the single change at residue 54 relative to Flap+(I54V) , does not. Yet, how Flap+(I54A) behaves in solution is not known. To understand the molecular basis of V54A evolution, we compared nuclear magnetic resonance (NMR) spectroscopy, fluorescence spectroscopy, isothermal titration calorimetry, and enzymatic assay data from four PR proteins: PR (pWT), Flap+(I54V) , Flap+(I54A) , and Flap+(I54) , a control mutant that contains only L10I, G48V and V82A mutations. Our data consistently show that selection to the smaller side chain at residue 54, not only decreases inhibitor affinity, but also restores the catalytic activity.
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Affiliation(s)
- Shahid N Khan
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - John D Persons
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Michel Guerrero
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Tatiana V Ilina
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Masayuki Oda
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Rieko Ishima
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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14
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Zondagh J, Basson AE, Achilonu I, Morris L, Dirr HW, Sayed Y. Drug susceptibility and replication capacity of a rare HIV-1 subtype C protease hinge region variant. Antivir Ther 2020; 24:333-342. [PMID: 30958309 DOI: 10.3851/imp3308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/10/2019] [Indexed: 10/27/2022]
Abstract
BACKGROUND Protease inhibitors form the main component of second-line antiretroviral treatment in South Africa. Despite their efficacy, mutations arising within the HIV-1 gag and protease coding regions contribute to the development of resistance against this class of drug. In this paper we investigate a South African HIV-1 subtype C Gag-protease that contains a hinge region mutation and insertion (N37T↑V). METHODS In vitro single-cycle drug susceptibility and viral replication capacity assays were performed on W1201i, a wild-type reference isolate (MJ4) and a chimeric construct (MJ4GagN37T↑VPR). Additionally, enzyme assays were performed on the N37T↑V protease and a wild-type reference protease. RESULTS W1201i showed a small (threefold), but significant (P<0.0001) reduction in drug susceptibility to darunavir compared with MJ4. Substitution of W1201i-Gag with MJ4-Gag resulted in an additional small (twofold), but significant (P<0.01) reduction in susceptibility to lopinavir and atazanavir. The W1201i pseudovirus had a significantly (P<0.01) reduced replication capacity (16.4%) compared with the MJ4. However, this was dramatically increased to 164% (P<0.05) when W1201i-Gag was substituted with MJ4-Gag. Furthermore, the N37T↑V protease displayed reduced catalytic processing compared with the SK154 protease. CONCLUSIONS Collectively, these data suggest that the N37T↑V mutation and insertion increases viral infectivity and decreases drug susceptibility. These variations are classified as secondary mutations, and indirectly impact inhibitor binding, enzyme fitness and enzyme stability. Additionally, polymorphisms arising in Gag can modify the impact of protease with regards to viral replication and susceptibility to protease inhibitors.
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Affiliation(s)
- Jake Zondagh
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of Witwatersrand, Johannesburg, South Africa
| | - Adriaan E Basson
- HIV Pathogenesis Research Unit, Department of Molecular Medicine and Haematology, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa.,Centre for HIV and STIs, National Institute for Communicable Diseases (NICD) of the National Health Laboratory Service (NHLS), Johannesburg, South Africa
| | - Ikechukwu Achilonu
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of Witwatersrand, Johannesburg, South Africa
| | - Lynn Morris
- Centre for HIV and STIs, National Institute for Communicable Diseases (NICD) of the National Health Laboratory Service (NHLS), Johannesburg, South Africa.,Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Heini W Dirr
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of Witwatersrand, Johannesburg, South Africa
| | - Yasien Sayed
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of Witwatersrand, Johannesburg, South Africa
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15
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Novel radial distribution function approach in the study of point mutations: the HIV-1 protease case study. Future Med Chem 2020; 12:1025-1036. [PMID: 32319305 DOI: 10.4155/fmc-2020-0042] [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] [Indexed: 11/17/2022] Open
Abstract
Background: Mutations are one of the engines of evolution. Under constant stress pressure, mutations can lead to the emergence of unwanted, drug-resistant entities. Methodology: The radial distribution function weighted by the number of valence shell electrons is used to design quantitative structure-activity relationship (QSAR) model relating descriptors with the inhibition constant for a series of wild-type HIV-1 protease inhibitor complexes. The residuals of complexes with mutant HIV-1 protease were correlated with the energy of the highest occupied molecular orbitals of the residues introduced to enzyme via point mutations. Conclusion: Successful identification of residues Ile3, Asp25, Val32 and Ile50 as the one whose substitution influences the inhibition constant the most, demonstrates the potential of the proposed methodology for the study of the effects of point mutations.
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16
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Voshavar C. Protease Inhibitors for the Treatment of HIV/AIDS: Recent Advances and Future Challenges. Curr Top Med Chem 2019; 19:1571-1598. [PMID: 31237209 DOI: 10.2174/1568026619666190619115243] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 05/22/2019] [Accepted: 05/27/2019] [Indexed: 02/07/2023]
Abstract
Acquired Immunodeficiency Syndrome (AIDS) is a chronic disease characterized by multiple life-threatening illnesses caused by a retro-virus, Human Immunodeficiency Virus (HIV). HIV infection slowly destroys the immune system and increases the risk of various other infections and diseases. Although, there is no immediate cure for HIV infection/AIDS, several drugs targeting various cruxes of HIV infection are used to slow down the progress of the disease and to boost the immune system. One of the key therapeutic strategies is Highly Active Antiretroviral Therapy (HAART) or ' AIDS cocktail' in a general sense, which is a customized combination of anti-retroviral drugs designed to combat the HIV infection. Since HAART's inception in 1995, this treatment was found to be effective in improving the life expectancy of HIV patients over two decades. Among various classes of HAART treatment regimen, Protease Inhibitors (PIs) are known to be widely used as a major component and found to be effective in treating HIV infection/AIDS. For the past several years, a variety of protease inhibitors have been reported. This review outlines the drug design strategies of PIs, chemical and pharmacological characteristics of some mechanism-based inhibitors, summarizes the recent developments in small molecule based drug discovery with HIV protease as a drug target. Further discussed are the pharmacology, PI drug resistance on HIV PR, adverse effects of HIV PIs and challenges/impediments in the successful application of HIV PIs as an important class of drugs in HAART regimen for the effective treatment of AIDS.
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Affiliation(s)
- Chandrashekhar Voshavar
- College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, FL 32307, United States
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17
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Ishima R, Kurt Yilmaz N, Schiffer CA. NMR and MD studies combined to elucidate inhibitor and water interactions of HIV-1 protease and their modulations with resistance mutations. JOURNAL OF BIOMOLECULAR NMR 2019; 73:365-374. [PMID: 31243634 PMCID: PMC6941145 DOI: 10.1007/s10858-019-00260-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 06/19/2019] [Indexed: 06/09/2023]
Abstract
Over the last two decades, both the sensitivity of NMR and the time scale of molecular dynamics (MD) simulation have increased tremendously and have advanced the field of protein dynamics. HIV-1 protease has been extensively studied using these two methods, and has presented a framework for cross-evaluation of structural ensembles and internal dynamics by integrating the two methods. Here, we review studies from our laboratories over the last several years, to understand the mechanistic basis of protease drug-resistance mutations and inhibitor responses, using NMR and crystal structure-based parallel MD simulations. Our studies demonstrate that NMR relaxation experiments, together with crystal structures and MD simulations, significantly contributed to the current understanding of structural/dynamic changes due to HIV-1 protease drug resistance mutations.
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Affiliation(s)
- Rieko Ishima
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Nese Kurt Yilmaz
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Celia A Schiffer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, USA.
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18
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Huang S, Zhang D, Mei H, Kevin M, Qu S, Pan X, Lu L. SMD-Based Interaction-Energy Fingerprints Can Predict Accurately the Dissociation Rate Constants of HIV-1 Protease Inhibitors. J Chem Inf Model 2018; 59:159-169. [DOI: 10.1021/acs.jcim.8b00567] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
| | | | | | | | | | - Xianchao Pan
- Department of Medicinal Chemistry, College of Pharmacy, Southwest Medical University, Luzhou, Sichuan 646000, China
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19
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Maphumulo SI, Halder AK, Govender T, Maseko S, Maguire GEM, Honarparvar B, Kruger HG. Exploring the flap dynamics of the South African HIV subtype C protease in presence of FDA-approved inhibitors: MD study. Chem Biol Drug Des 2018; 92:1899-1913. [PMID: 30003668 DOI: 10.1111/cbdd.13364] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 07/09/2018] [Indexed: 01/01/2023]
Abstract
HIV-1 protease (HIV PR) is considered as one of the most attractive targets for the treatment of HIV and the impact of flap dynamics of HIV PR on the binding affinities of protease inhibitors (PIs) is a crucial ongoing research field. Recently, our research group evaluated the binding affinities of different FDA approved PIs against the South African HIV-1 subtype C (C-SA) protease (PR). The CSA-HIV PR displayed weaker binding affinity for most of the clinical PIs compared to HIV-1 B subtype for West and Central Europe, the Americas. In the current work, the flap dynamics of four different systems of HIV-1 C-SA PR complexed to FDA approved second generation PIs and its impact on binding was explored over the molecular dynamic trajectories. It was observed that the interactions of the selected drugs with the binding site residues of the protease may not be the major contributor for affinity towards PIs. Various post-MD analyses were performed, also entropic contributions, solvation free energies and hydrophobic core formation interactions were studied to assess how the flap dynamics of C-SA PR which is affected by such factors. From these contributions, large van der Waals interactions and low solvation free energies were found to be major factors for the higher activity of ATV against C-SA HIV PR. Furthermore, a comparatively stable hydrophobic core may be responsible for higher stability of the PR flaps of the ATV complex. The outcome of this study provides significant guidance to how the flap dynamics of C-SA PR is affected by various factors as a result of the binding affinity of various protease inhibitors. It will also assist with the design of potent inhibitors against C-SA HIV PR that apart from binding in the active site of PR can interacts with the flaps to prevent opening of the flaps resulting in inactivation of the protease.
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Affiliation(s)
- Siyabonga I Maphumulo
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Amit K Halder
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Thavendran Govender
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Sibusiso Maseko
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Glenn E M Maguire
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa.,School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa
| | - Bahareh Honarparvar
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Hendrik G Kruger
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
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20
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Thacker JCR, Vincent MA, Popelier PLA. Using the Relative Energy Gradient Method with Interacting Quantum Atoms to Determine the Reaction Mechanism and Catalytic Effects in the Peptide Hydrolysis in HIV-1 Protease. Chemistry 2018; 24:11200-11210. [PMID: 29802794 PMCID: PMC6099506 DOI: 10.1002/chem.201802035] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Indexed: 11/10/2022]
Abstract
The reaction mechanism in an active site is of the utmost importance when trying to understand the role that an enzyme plays in biological processes. In a recently published paper [Theor. Chem. Acc. 2017, 136, 86], we formalised the Relative Energy Gradient (REG) method for automating an Interacting Quantum Atoms (IQA) analysis. Here, the REG method is utilised to determine the mechanism of peptide hydrolysis in the aspartic active site of the enzyme HIV-1 Protease. Using the REG method along with the IQA approach we determine the mechanism of peptide hydrolysis without employing any arbitrary parameters and with remarkable ease (albeit at large computational cost: the system contains 133 atoms, which means that there are 17 689 individual IQA terms to be calculated). When REG and IQA work together it is possible to determine a reaction mechanism at atomistic resolution from data directly derived from quantum calculations, without arbitrary parameters. Moreover, the mechanism determined by this novel method gives concrete insight into how the active site residues catalyse peptide hydrolysis.
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Affiliation(s)
- Joseph C. R. Thacker
- Manchester Institute of Biotechnology (MIB)131 Princess StreetManchesterM1 7DNUK
- School of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK
| | - Mark A. Vincent
- Manchester Institute of Biotechnology (MIB)131 Princess StreetManchesterM1 7DNUK
- School of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK
| | - Paul L. A. Popelier
- Manchester Institute of Biotechnology (MIB)131 Princess StreetManchesterM1 7DNUK
- School of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK
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21
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Wapling J, Srivastava S, Shehu-Xhilaga M, Tachedjian G. Targeting Human Immunodeficiency Virus Type 1 Assembly, Maturation and Budding. Drug Target Insights 2017. [DOI: 10.1177/117739280700200020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Johanna Wapling
- Molecular Interactions Group, Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, 3004, Australia
- Department of Microbiology, Monash University, Clayton, Victoria 3168, Australia
| | - Seema Srivastava
- Molecular Interactions Group, Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, 3004, Australia
| | - Miranda Shehu-Xhilaga
- Department of Medicine, Monash University, Prahran, Victoria 3181, Australia
- Infectious Diseases Unit, Alfred Hospital, Prahran, Victoria 3181, Australia
| | - Gilda Tachedjian
- Molecular Interactions Group, Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, 3004, Australia
- Department of Microbiology, Monash University, Clayton, Victoria 3168, Australia
- Department of Medicine, Monash University, Prahran, Victoria 3181, Australia
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22
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Evolution of inhibitor-resistant natural mutant forms of HIV-1 protease probed by pre-steady state kinetic analysis. Biochimie 2017; 142:125-134. [PMID: 28843613 DOI: 10.1016/j.biochi.2017.08.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 08/21/2017] [Indexed: 11/23/2022]
Abstract
Pre-steady state kinetic analysis of mechanistic features of substrate binding and processing is crucial for insight into the evolution of inhibitor-resistant forms of HIV-1 protease. These data may provide a correct vector for rational drug design assuming possible intrinsic dynamic effects. These data should also give some clues to the molecular mechanism of protease action and resistance to inhibitors. Here we report pre-steady state kinetics of the interaction of wild type or mutant forms of HIV-1 protease with a FRET-labeled peptide. The three-stage "minimal" kinetic scheme with first and second reversible steps of substrate binding and with following irreversible peptide cleavage step adequately described experimental data. For the first time, a set of "elementary" kinetic parameters of wild type HIV-1 protease and its natural mutant inhibitor-resistant forms MDR-HM, ANAM-11 and prDRV4 were compared. Inhibitors of the first and second generation were used to estimate the inhibitory effects on HIV-1 protease activity. The resulting set of kinetic data supported that the mutant forms are kinetically unaffected by inhibitors of the first generation, proving their functional resistance to these compounds. The second generation inhibitor darunavir inhibited mutant forms MDR-HM and ANAM-11, but was ineffective against prDRV4. Our kinetic data revealed that these inhibitors induced different conformational changes in the enzyme and, thereby they have different mode of binding in the enzyme active site. These data confirmed hypothesis that the driving force of the inhibitor-resistance evolution is disruption of enzyme-inhibitor complex by changing of the contact network in the inhibitor binding site.
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23
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White JT, Toptygin D, Cohen R, Murphy N, Hilser VJ. Structural Stability of the Coiled-Coil Domain of Tumor Susceptibility Gene (TSG)-101. Biochemistry 2017; 56:4646-4655. [PMID: 28776372 PMCID: PMC5616090 DOI: 10.1021/acs.biochem.7b00469] [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] [Indexed: 01/19/2023]
Abstract
![]()
The
tumor susceptibility gene-101 coiled coil domain (TSG101cc)
is an integral component of the endosomal maturation machinery and
cytokinesis, and also interacts with several transcription factors.
The TSG101cc has been crystallized as a homotetramer but is known
to interact with two of its binding partners as a heterotrimer. To
investigate this apparent discrepancy, we examined the solution thermodynamics
of the TSG101cc. Here, we use circular dichroism, differential scanning
calorimetry, analytical ultracentrifugation, fluorescence, and structural
thermodynamic analysis to investigate the structural stability and
the unfolding of the TSG101cc. We demonstrate that TSG101cc exists
in solution primarily as a tetramer, which unfolds in a two-state
manner. Surprisingly, no homodimeric or homotrimeric species were
detected. Structural thermodynamic analysis of the homotetrameric
structure and comparison with known oligomeric coiled-coils suggests
that the TSG101cc homotetramer is comparatively unstable on a per
residue basis. Furthermore, the homotrimeric coiled-coil is predicted
to be much less stable than the functional heterotrimeric coiled-coil
in the endosomal sorting complex required for transport 1 (ESCRT1).
These results support a model whereby the tetramer–monomer
equilibrium of TSG101 serves as the cellular reservoir of TSG101,
which is effectively outcompeted when its binding partners are present
and the heteroternary complex can form.
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Affiliation(s)
- Jordan T White
- Department of Biology, Johns Hopkins University , 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Dmitri Toptygin
- Department of Biology, Johns Hopkins University , 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Randy Cohen
- Department of Biology, Johns Hopkins University , 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Natalie Murphy
- Department of Biology, Johns Hopkins University , 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Vincent J Hilser
- Department of Biology, Johns Hopkins University , 3400 North Charles Street, Baltimore, Maryland 21218, United States
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24
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Shi S, Nguyen PK, Cabral HJ, Diez-Barroso R, Derry PJ, Kanahara SM, Kumar VA. Development of peptide inhibitors of HIV transmission. Bioact Mater 2016; 1:109-121. [PMID: 29744399 PMCID: PMC5883972 DOI: 10.1016/j.bioactmat.2016.09.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/18/2016] [Accepted: 09/07/2016] [Indexed: 12/26/2022] Open
Abstract
Treatment of HIV has long faced the challenge of high mutation rates leading to rapid development of resistance, with ongoing need to develop new methods to effectively fight the infection. Traditionally, early HIV medications were designed to inhibit RNA replication and protein production through small molecular drugs. Peptide based therapeutics are a versatile, promising field in HIV therapy, which continues to develop as we expand our understanding of key protein-protein interactions that occur in HIV replication and infection. This review begins with an introduction to HIV, followed by the biological basis of disease, current clinical management of the disease, therapeutics on the market, and finally potential avenues for improved drug development.
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Key Words
- AIDS, acquired immunodeficiency syndrome
- ART, antiretroviral therapy
- CDC, Centers for Disease Control and Prevention
- Drug development
- FDA, US Food and Drug Administration
- FY, fiscal year
- HAART, highly active antiretroviral therapy
- HCV, hepatitis C Virus
- HIV
- HIV treatment
- HIV, human immunodeficiency virus
- INSTI, Integrase strand transfer inhibitors
- LEDGF, lens epithelium-derived growth factor
- NNRTI, Non-nucleoside reverse transcriptase inhibitors
- NRTI, Nucleoside/Nucleotide Reverse Transcriptase Inhibitors
- Peptide inhibitor
- Peptide therapeutic
- R&D, research and development
- RT, reverse transcriptase
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Affiliation(s)
- Siyu Shi
- Department of Chemistry, Rice University, Houston, TX 77030, USA
| | - Peter K. Nguyen
- Department of Biomedical Engineering, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA
- Department of Chemical, Biological and Pharmaceutical Engineering, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA
| | - Henry J. Cabral
- Department of Biomedical Engineering, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA
- Department of Chemical, Biological and Pharmaceutical Engineering, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA
| | | | - Paul J. Derry
- Department of Chemistry, Rice University, Houston, TX 77030, USA
| | | | - Vivek A. Kumar
- Department of Biomedical Engineering, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA
- Department of Chemical, Biological and Pharmaceutical Engineering, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA
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25
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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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26
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Ghosh AK, Osswald HL, Prato G. Recent Progress in the Development of HIV-1 Protease Inhibitors for the Treatment of HIV/AIDS. J Med Chem 2016; 59:5172-208. [PMID: 26799988 PMCID: PMC5598487 DOI: 10.1021/acs.jmedchem.5b01697] [Citation(s) in RCA: 282] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
HIV-1 protease inhibitors continue to play an important role in the treatment of HIV/AIDS, transforming this deadly ailment into a more manageable chronic infection. Over the years, intensive research has led to a variety of approved protease inhibitors for the treatment of HIV/AIDS. In this review, we outline current drug design and medicinal chemistry efforts toward the development of next-generation protease inhibitors beyond the currently approved drugs.
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Affiliation(s)
- Arun K. Ghosh
- Department of Chemistry and Department of Medicinal Chemistry, Purdue University, West Lafayette, IN 47907
| | - Heather L. Osswald
- Department of Chemistry and Department of Medicinal Chemistry, Purdue University, West Lafayette, IN 47907
| | - Gary Prato
- Department of Chemistry and Department of Medicinal Chemistry, Purdue University, West Lafayette, IN 47907
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27
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Pietrucci F, Vargiu AV, Kranjc A. HIV-1 Protease Dimerization Dynamics Reveals a Transient Druggable Binding Pocket at the Interface. Sci Rep 2015; 5:18555. [PMID: 26692118 PMCID: PMC4686983 DOI: 10.1038/srep18555] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 11/19/2015] [Indexed: 12/30/2022] Open
Abstract
The binding mechanism of HIV-1 protease monomers leading to the catalytically competent dimeric enzyme has been investigated by means of state-of-the-art atomistic simulations. The emerging picture allows a deeper understanding of experimental observations and reveals that water molecules trapped at the interface have an important role in slowing down the kinetics of the association process. Unexpectedly, a cryptic binding pocket is identified at the interface of the complex, corresponding to a partially bound dimer that lacks enzymatic function. The pocket has a transient nature with a lifetime longer than 1 μs, and it displays very favorable druggability features. Docking as well as MM-GBSA free-energy calculations further support the possibility to target the new binding site by means of inhibitors able to prevent the complete dimerization by capturing the inactive conformation. This discovery could open the way to the rational design of a new class of anti-HIV drugs.
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Affiliation(s)
- Fabio Pietrucci
- Sorbonne Universités, UPMC University Paris 6, CNRS - UMR 7590, IMPMC, F-75005 Paris, France
| | | | - Agata Kranjc
- School of Pharmaceutical Sciences, University of Geneva, CH-1211 Geneva, Switzerland
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28
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Clarkson BR, Schön A, Freire E. Conformational stability and self-association equilibrium in biologics. Drug Discov Today 2015; 21:342-7. [PMID: 26608889 DOI: 10.1016/j.drudis.2015.11.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 10/20/2015] [Accepted: 11/12/2015] [Indexed: 12/22/2022]
Abstract
Biologics exist in equilibrium between native, partially denatured, and denatured conformational states. The population of any of these states is dictated by their Gibbs energy and can be altered by changes in physical and solution conditions. Some conformations have a tendency to self-associate and aggregate, an undesirable phenomenon in protein therapeutics. Conformational equilibrium and self-association are linked thermodynamic functions. Given that any associative reaction is concentration dependent, conformational stability studies performed at different protein concentrations can provide early clues to future aggregation problems. This analysis can be applied to the selection of protein variants or the identification of better formulation solutions. In this review, we discuss three different aggregation situations and their manifestation in the observed conformational equilibrium of a protein.
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Affiliation(s)
| | - Arne Schön
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Ernesto Freire
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA.
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29
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Chauhan J, Chen SE, Fenstermacher KJ, Naser-Tavakolian A, Reingewertz T, Salmo R, Lee C, Williams E, Raje M, Sundberg E, DeStefano JJ, Freire E, Fletcher S. Synthetic, structural mimetics of the β-hairpin flap of HIV-1 protease inhibit enzyme function. Bioorg Med Chem 2015; 23:7095-109. [PMID: 26474665 DOI: 10.1016/j.bmc.2015.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 08/20/2015] [Accepted: 09/03/2015] [Indexed: 01/11/2023]
Abstract
Small-molecule mimetics of the β-hairpin flap of HIV-1 protease (HIV-1 PR) were designed based on a 1,4-benzodiazepine scaffold as a strategy to interfere with the flap-flap protein-protein interaction, which functions as a gated mechanism to control access to the active site. Michaelis-Menten kinetics suggested our small-molecules are competitive inhibitors, which indicates the mode of inhibition is through binding the active site or sterically blocking access to the active site and preventing flap closure, as designed. More generally, a new bioactive scaffold for HIV-1PR inhibition has been discovered, with the most potent compound inhibiting the protease with a modest K(i) of 11 μM.
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Affiliation(s)
- Jay Chauhan
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 N. Pine St., Baltimore, MD 21201, USA
| | - Shen-En Chen
- Department of Biology, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
| | - Katherine J Fenstermacher
- Department of Cell Biology & Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Aurash Naser-Tavakolian
- Department of Biology, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
| | - Tali Reingewertz
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 725 West Lombard St., Baltimore, MD 21201, USA
| | - Rosene Salmo
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 N. Pine St., Baltimore, MD 21201, USA
| | - Christian Lee
- PharmD Program, University of Maryland School of Pharmacy, 20 N. Pine St., Baltimore, MD 21201, USA
| | - Emori Williams
- Vivien T Thomas Medical Arts Academy, 100 N Calhoun St., Baltimore, MD 21223, USA
| | - Mithun Raje
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 N. Pine St., Baltimore, MD 21201, USA
| | - Eric Sundberg
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 725 West Lombard St., Baltimore, MD 21201, USA
| | - Jeffrey J DeStefano
- Department of Cell Biology & Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Ernesto Freire
- Department of Biology, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
| | - Steven Fletcher
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 N. Pine St., Baltimore, MD 21201, USA; University of Maryland Greenebaum Cancer Center, 22 S. Greene St., Baltimore, MD 21201, USA.
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30
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Rehan S, Ashok Y, Nanekar R, Jaakola VP. Thermodynamics and kinetics of inhibitor binding to human equilibrative nucleoside transporter subtype-1. Biochem Pharmacol 2015; 98:681-9. [PMID: 26428002 DOI: 10.1016/j.bcp.2015.09.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 09/24/2015] [Indexed: 10/23/2022]
Abstract
Many nucleoside transport inhibitors are in clinical use as anti-cancer, vasodilator and cardioprotective drugs. However, little is known about the binding energetics of these inhibitors to nucleoside transporters (NTs) due to their low endogenous expression levels and difficulties in the biophysical characterization of purified protein with ligands. Here, we present kinetics and thermodynamic analyses of inhibitor binding to the human equilibrative nucleoside transporter-1 (hENT1), also known as SLC29A1. Using a radioligand binding assay, we obtained equilibrium binding and kinetic rate constants of well-known NT inhibitors--[(3)H]nitrobenzylmercaptopurine ribonucleoside ([(3)H]NBMPR), dilazep, and dipyridamole--and the native permeant, adenosine, to hENT1. We observed that the equilibrium binding affinities for all inhibitors decreased whereas, the kinetic rate constants increased with increasing temperature. Furthermore, we found that binding is enthalpy driven and thus, an exothermic reaction, implying that the transporter does not discriminate between its inhibitors and substrates thermodynamically. This predominantly enthalpy-driven binding by four chemically distinct ligands suggests that the transporter may not tolerate diversity in the type of interactions that lead to high affinity binding. Consistent with this, the measured activation energy of [(3)H]NBMPR association was relatively large (20 kcal mol(-1)) suggesting a conformational change upon inhibitor binding. For all three inhibitors the enthalpy (ΔH°) and entropy (ΔS°) contributions to the reaction energetics were determined by van't Hoff analysis to be roughly similar (25-75% ΔG°). Gains in enthalpy with increasing polar surface area of inhibitors suggest that the binding is favored by electrostatic or polar interactions between the ligands and the transporter.
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Affiliation(s)
- Shahid Rehan
- Oulu Biocenter and Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
| | - Yashwanth Ashok
- Oulu Biocenter and Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
| | - Rahul Nanekar
- Oulu Biocenter and Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
| | - Veli-Pekka Jaakola
- Oulu Biocenter and Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland.
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31
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Fluorogenic Assay for Inhibitors of HIV-1 Protease with Sub-picomolar Affinity. Sci Rep 2015; 5:11286. [PMID: 26261098 PMCID: PMC4531283 DOI: 10.1038/srep11286] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 05/14/2015] [Indexed: 11/17/2022] Open
Abstract
A fluorogenic substrate for HIV-1 protease was designed and used as the basis for a hypersensitive assay. The substrate exhibits a kcat of 7.4 s−1, KM of 15 μM, and an increase in fluorescence intensity of 104-fold upon cleavage, thus providing sensitivity that is unmatched in a continuous assay of HIV-1 protease. These properties enabled the enzyme concentration in an activity assay to be reduced to 25 pM, which is close to the Kd value of the protease dimer. By fitting inhibition data to Morrison’s equation, Ki values of amprenavir, darunavir, and tipranavir were determined to be 135, 10, and 82 pM, respectively. This assay, which is capable of measuring Ki values as low as 0.25 pM, is well-suited for characterizing the next generation of HIV-1 protease inhibitors.
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32
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Denatured state aggregation parameters derived from concentration dependence of protein stability. Anal Biochem 2015; 488:45-50. [PMID: 26239214 DOI: 10.1016/j.ab.2015.07.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 07/20/2015] [Accepted: 07/23/2015] [Indexed: 12/30/2022]
Abstract
Protein aggregation is a major issue affecting the long-term stability of protein preparations. Proteins exist in equilibrium between the native and denatured or partially denatured conformations. Often denatured or partially denatured conformations are prone to aggregate because they expose to solvent the hydrophobic core of the protein. The aggregation of denatured protein gradually shifts the protein equilibrium toward increasing amounts of denatured and ultimately aggregated protein. Recognizing and quantitating the presence of denatured protein and its aggregation at the earliest possible time will bring enormous benefits to the identification and selection of optimal solvent conditions or the engineering of proteins with the best stability/aggregation profile. In this article, a new approach that allows simultaneous determination of structural stability and the amount of denatured and aggregated protein is presented. This approach is based on the analysis of the concentration dependence of the Gibbs energy (ΔG) of protein stability. It is shown that three important quantities can be evaluated simultaneously: (i) the population of denatured protein, (ii) the population of aggregated protein, and (iii) the fraction of denatured protein that is aggregated.
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33
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Huang YMM, Kang M, Chang CEA. Switches of hydrogen bonds during ligand-protein association processes determine binding kinetics. J Mol Recognit 2015; 27:537-48. [PMID: 25042708 DOI: 10.1002/jmr.2377] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 03/22/2014] [Accepted: 03/24/2014] [Indexed: 11/05/2022]
Abstract
Revealing the processes of ligand-protein associations deepens our understanding of molecular recognition and binding kinetics. Hydrogen bonds (H-bonds) play a crucial role in optimizing ligand-protein interactions and ligand specificity. In addition to the formation of stable H-bonds in the final bound state, the formation of transient H-bonds during binding processes contributes binding kinetics that define a ligand as a fast or slow binder, which also affects drug action. However, the effect of forming the transient H-bonds on the kinetic properties is little understood. Guided by results from coarse-grained Brownian dynamics simulations, we used classical molecular dynamics simulations in an implicit solvent model and accelerated molecular dynamics simulations in explicit waters to show that the position and distribution of the H-bond donor or acceptor of a drug result in switching intermolecular and intramolecular H-bond pairs during ligand recognition processes. We studied two major types of HIV-1 protease ligands: a fast binder, xk263, and a slow binder, ritonavir. The slow association rate in ritonavir can be attributed to increased flexibility of ritonavir, which yields multistep transitions and stepwise entering patterns and the formation and breaking of complex H-bond pairs during the binding process. This model suggests the importance of conversions of spatiotemporal H-bonds during the association of ligands and proteins, which helps in designing inhibitors with preferred binding kinetics.
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Affiliation(s)
- Yu-ming M Huang
- Department of Chemistry, University of California, Riverside, CA, 92521, USA
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34
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Caldarini M, Sonar P, Valpapuram I, Tavella D, Volonté C, Pandini V, Vanoni M, Aliverti A, Broglia R, Tiana G, Cecconi C. The complex folding behavior of HIV-1-protease monomer revealed by optical-tweezer single-molecule experiments and molecular dynamics simulations. Biophys Chem 2014; 195:32-42. [DOI: 10.1016/j.bpc.2014.08.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 08/04/2014] [Accepted: 08/04/2014] [Indexed: 12/11/2022]
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35
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Naicker P, Stoychev S, Dirr HW, Sayed Y. Amide hydrogen exchange in HIV-1 subtype B and C proteases - insights into reduced drug susceptibility and dimer stability. FEBS J 2014; 281:5395-410. [DOI: 10.1111/febs.13084] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 08/29/2014] [Accepted: 09/29/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Previn Naicker
- Protein Structure-Function Research Unit; School of Molecular and Cell Biology; University of the Witwatersrand; Johannesburg South Africa
| | - Stoyan Stoychev
- Council for Scientific and Industrial Research; Biosciences; Pretoria South Africa
| | - Heini W. Dirr
- Protein Structure-Function Research Unit; School of Molecular and Cell Biology; University of the Witwatersrand; Johannesburg South Africa
| | - Yasien Sayed
- Protein Structure-Function Research Unit; School of Molecular and Cell Biology; University of the Witwatersrand; Johannesburg South Africa
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36
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Kutálková E, Hrnčiřík J, Ingr M. Pressure induced structural changes and dimer destabilization of HIV-1 protease studied by molecular dynamics simulations. Phys Chem Chem Phys 2014; 16:25906-15. [DOI: 10.1039/c4cp03676j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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37
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Mbita Z, Hull R, Dlamini Z. Human immunodeficiency virus-1 (HIV-1)-mediated apoptosis: new therapeutic targets. Viruses 2014; 6:3181-227. [PMID: 25196285 PMCID: PMC4147692 DOI: 10.3390/v6083181] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 06/12/2014] [Accepted: 07/08/2014] [Indexed: 12/18/2022] Open
Abstract
HIV has posed a significant challenge due to the ability of the virus to both impair and evade the host’s immune system. One of the most important mechanisms it has employed to do so is the modulation of the host’s native apoptotic pathways and mechanisms. Viral proteins alter normal apoptotic signaling resulting in increased viral load and the formation of viral reservoirs which ultimately increase infectivity. Both the host’s pro- and anti-apoptotic responses are regulated by the interactions of viral proteins with cell surface receptors or apoptotic pathway components. This dynamic has led to the development of therapies aimed at altering the ability of the virus to modulate apoptotic pathways. These therapies are aimed at preventing or inhibiting viral infection, or treating viral associated pathologies. These drugs target both the viral proteins and the apoptotic pathways of the host. This review will examine the cell types targeted by HIV, the surface receptors exploited by the virus and the mechanisms whereby HIV encoded proteins influence the apoptotic pathways. The viral manipulation of the hosts’ cell type to evade the immune system, establish viral reservoirs and enhance viral proliferation will be reviewed. The pathologies associated with the ability of HIV to alter apoptotic signaling and the drugs and therapies currently under development that target the ability of apoptotic signaling within HIV infection will also be discussed.
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Affiliation(s)
- Zukile Mbita
- College of Agriculture and Environmental Sciences, University of South Africa, Florida Science Campus, C/o Christiaan de Wet and Pioneer Avenue P/Bag X6, Johannesburg 1710, South Africa.
| | - Rodney Hull
- College of Agriculture and Environmental Sciences, University of South Africa, Florida Science Campus, C/o Christiaan de Wet and Pioneer Avenue P/Bag X6, Johannesburg 1710, South Africa.
| | - Zodwa Dlamini
- College of Agriculture and Environmental Sciences, University of South Africa, Florida Science Campus, C/o Christiaan de Wet and Pioneer Avenue P/Bag X6, Johannesburg 1710, South Africa.
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38
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Dimerization of HIV-1 protease occurs through two steps relating to the mechanism of protease dimerization inhibition by darunavir. Proc Natl Acad Sci U S A 2014; 111:12234-9. [PMID: 25092296 DOI: 10.1073/pnas.1400027111] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dimerization of HIV-1 protease (PR) subunits is an essential process for PR's acquisition of proteolytic activity, which plays a critical role in the maturation of HIV-1. Recombinant wild-type PR (PR(WT)) proved to dimerize, as examined with electrospray ionization mass spectrometry; however, two active site interface PR mutants (PR(T26A) and PR(R87K)) remained monomeric. On the other hand, two termini interface PR mutants (PR(1-C95A) and PR(97/99)) took both monomeric and dimeric forms. Differential scanning fluorimetry indicated that PR(1-C95A) and PR(97/99) dimers were substantially less stable than PR(WT) dimers. These data indicate that intermolecular interactions of two monomers occur first at the active site interface, generating unstable or transient dimers, and interactions at the termini interface subsequently occur, generating stable dimers. Darunavir (DRV), an HIV-1 protease inhibitor, inhibits not only proteolytic activity but also PR dimerization. DRV bound to protease monomers in a one-to-one molar ratio, inhibiting the first step of PR dimerization, whereas conventional protease inhibitors (such as saquinavir) that inhibit enzymatic activity but not dimerization failed to bind to monomers. DRV also bound to mutant PRs containing the transframe region-added PR (TFR-PR(D25N) and TFR-PR(D25N-7AA)), whereas saquinavir did not bind to TFR-PR(D25N) or TFR-PR(D25N-7AA). Notably, DRV failed to bind to mutant PR containing four amino acid substitutions (V32I, L33F, I54M, and I84V) that confer resistance to DRV on HIV-1. To our knowledge, the present report represents the first demonstration of the two-step PR dimerization dynamics and the mechanism of dimerization inhibition by DRV, which should help design further, more potent novel PIs.
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39
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Huang X, Britto MD, Kear-Scott JL, Boone CD, Rocca JR, Simmerling C, Mckenna R, Bieri M, Gooley PR, Dunn BM, Fanucci GE. The role of select subtype polymorphisms on HIV-1 protease conformational sampling and dynamics. J Biol Chem 2014; 289:17203-14. [PMID: 24742668 DOI: 10.1074/jbc.m114.571836] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
HIV-1 protease is an essential enzyme for viral particle maturation and is a target in the fight against HIV-1 infection worldwide. Several natural polymorphisms are also associated with drug resistance. Here, we utilized both pulsed electron double resonance, also called double electron-electron resonance, and NMR (15)N relaxation measurements to characterize equilibrium conformational sampling and backbone dynamics of an HIV-1 protease construct containing four specific natural polymorphisms commonly found in subtypes A, F, and CRF_01 A/E. Results show enhanced backbone dynamics, particularly in the flap region, and the persistence of a novel conformational ensemble that we hypothesize is an alternative flap orientation of a curled open state or an asymmetric configuration when interacting with inhibitors.
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Affiliation(s)
- Xi Huang
- From the Department of Chemistry, University of Florida, Gainesville, Florida 32611
| | - Manuel D Britto
- From the Department of Chemistry, University of Florida, Gainesville, Florida 32611
| | - Jamie L Kear-Scott
- From the Department of Chemistry, University of Florida, Gainesville, Florida 32611
| | - Christopher D Boone
- the Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610
| | - James R Rocca
- the Advanced Magnetic Resonance Imaging and Spectroscopy Facility, McKnight Brain Institute, University of Florida, Gainesville, Florida 32610
| | - Carlos Simmerling
- the Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, and
| | - Robert Mckenna
- the Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610
| | - Michael Bieri
- the Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Paul R Gooley
- the Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Ben M Dunn
- 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,
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40
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Understanding HIV-1 protease autoprocessing for novel therapeutic development. Future Med Chem 2014; 5:1215-29. [PMID: 23859204 DOI: 10.4155/fmc.13.89] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In the infected cell, HIV-1 protease (PR) is initially synthesized as part of the GagPol polyprotein. PR autoprocessing is a virus-specific process by which the PR domain embedded in the precursor catalyzes proteolytic reactions responsible for liberation of free mature PRs, which then recognize and cleave at least ten different peptide sequences in the Gag and GagPol polyproteins. Despite extensive structure and function studies of the mature PRs as well as the successful development of ten US FDA-approved catalytic-site inhibitors, the precursor autoprocessing mechanism remains an intriguing yet-to-be-solved puzzle. This article discusses current understanding of the autoprocessing mechanism, in an effort to prompt the development of novel anti-HIV drugs that selectively target precursor autoprocessing.
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41
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Fanelli R, Ressurreição AS, Dufau L, Soulier JL, Vidu A, Tonali N, Bernadat G, Reboud-Ravaux M, Ongeri S. Introduction of polar groups on the naphthalene scaffold of molecular tongs inhibiting wild-type and mutated HIV-1 protease dimerization. MEDCHEMCOMM 2014. [DOI: 10.1039/c4md00032c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new series of naphthalene-based molecular tongs containing polar groups at the 3-position of the naphthalene scaffold was synthesized and its anti-dimerization activity was evaluated against HIV-1 protease.
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Affiliation(s)
- R. Fanelli
- Molécules Fluorées et Chimie Médicinale
- BioCIS UMR-CNRS 8076
- LabEx LERMIT
- Université Paris-Sud
- Faculté de Pharmacie
| | - A. S. Ressurreição
- Molécules Fluorées et Chimie Médicinale
- BioCIS UMR-CNRS 8076
- LabEx LERMIT
- Université Paris-Sud
- Faculté de Pharmacie
| | - L. Dufau
- Sorbonne Universités
- UPMC Univ Paris 06
- UMR 8256
- B2A
- Biological Adaptation and Ageing, Integrated Cellular Ageing and Inflammation, Molecular & Functional Enzymology
| | - J.-L. Soulier
- Molécules Fluorées et Chimie Médicinale
- BioCIS UMR-CNRS 8076
- LabEx LERMIT
- Université Paris-Sud
- Faculté de Pharmacie
| | - A. Vidu
- Molécules Fluorées et Chimie Médicinale
- BioCIS UMR-CNRS 8076
- LabEx LERMIT
- Université Paris-Sud
- Faculté de Pharmacie
| | - N. Tonali
- Molécules Fluorées et Chimie Médicinale
- BioCIS UMR-CNRS 8076
- LabEx LERMIT
- Université Paris-Sud
- Faculté de Pharmacie
| | - G. Bernadat
- Molécules Fluorées et Chimie Médicinale
- BioCIS UMR-CNRS 8076
- LabEx LERMIT
- Université Paris-Sud
- Faculté de Pharmacie
| | - M. Reboud-Ravaux
- Sorbonne Universités
- UPMC Univ Paris 06
- UMR 8256
- B2A
- Biological Adaptation and Ageing, Integrated Cellular Ageing and Inflammation, Molecular & Functional Enzymology
| | - S. Ongeri
- Molécules Fluorées et Chimie Médicinale
- BioCIS UMR-CNRS 8076
- LabEx LERMIT
- Université Paris-Sud
- Faculté de Pharmacie
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42
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F99 is Critical for Dimerization and Activation of South African HIV-1 Subtype C Protease. Protein J 2013; 32:560-7. [DOI: 10.1007/s10930-013-9517-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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43
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Ko E, Raghuraman A, Perez LM, Ioerger TR, Burgess K. Exploring key orientations at protein-protein interfaces with small molecule probes. J Am Chem Soc 2013; 135:167-73. [PMID: 23270593 PMCID: PMC3551583 DOI: 10.1021/ja3067258] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Small molecule probes that selectively perturb protein-protein interactions (PPIs) are pivotal to biomedical science, but their discovery is challenging. We hypothesized that conformational resemblance of semirigid scaffolds expressing amino acid side-chains to PPI-interface regions could guide this process. Consequently, a data mining algorithm was developed to sample huge numbers of PPIs to find ones that match preferred conformers of a selected semirigid scaffold. Conformations of one such chemotype (1aaa; all methyl side-chains) matched several biomedically significant PPIs, including the dimerization interface of HIV-1 protease. On the basis of these observations, four molecules 1 with side-chains corresponding to the matching HIV-1 dimerization interface regions were prepared; all four inhibited HIV-1 protease via perturbation of dimerization. These data indicate this approach may inspire design of small molecule interface probes to perturb PPIs.
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Affiliation(s)
- Eunhwa Ko
- Department of Chemistry, Texas A & M University, Box 30012, College Station, TX 77842
| | - Arjun Raghuraman
- Department of Chemistry, Texas A & M University, Box 30012, College Station, TX 77842
| | - Lisa M. Perez
- Laboratory for Molecular Simulation, Texas A & M University, Box 30012, College Station, TX 77842
| | - Thomas R. Ioerger
- Department of Computer Science, Texas A & M University, College Station, TX 77843-3112
| | - Kevin Burgess
- Department of Chemistry, Texas A & M University, Box 30012, College Station, TX 77842
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44
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Doyle CM, Rumfeldt JA, Broom HR, Broom A, Stathopulos PB, Vassall KA, Almey JJ, Meiering EM. Energetics of oligomeric protein folding and association. Arch Biochem Biophys 2012; 531:44-64. [PMID: 23246784 DOI: 10.1016/j.abb.2012.12.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 11/29/2012] [Accepted: 12/05/2012] [Indexed: 12/11/2022]
Abstract
In nature, proteins most often exist as complexes, with many of these consisting of identical subunits. Understanding of the energetics governing the folding and misfolding of such homooligomeric proteins is central to understanding their function and misfunction, in disease or biotechnology. Much progress has been made in defining the mechanisms and thermodynamics of homooligomeric protein folding. In this review, we outline models as well as calorimetric and spectroscopic methods for characterizing oligomer folding, and describe extensive results obtained for diverse proteins, ranging from dimers to octamers and higher order aggregates. To our knowledge, this area has not been reviewed comprehensively in years, and the collective progress is impressive. The results provide evolutionary insights into the development of subunit interfaces, mechanisms of oligomer folding, and contributions of oligomerization to protein stability, function and regulation. Thermodynamic analyses have also proven valuable for understanding protein misfolding and aggregation mechanisms, suggesting new therapeutic avenues. Successful recent designs of novel, functional proteins demonstrate increased understanding of oligomer folding. Further rigorous analyses using multiple experimental and computational approaches are still required, however, to achieve consistent and accurate prediction of oligomer folding energetics. Modeling the energetics remains challenging but is a promising avenue for future advances.
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Affiliation(s)
- Colleen M Doyle
- Guelph-Waterloo Centre for Graduate Studies in Chemistry and Biochemistry, and Department of Chemistry, University of Waterloo, 200 University Ave. West, Waterloo, ON, Canada
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45
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Kimura S, Broglia RA, Tiana G. Thermodynamics of strongly allosteric inhibition: a model study of HIV-1 protease. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2012; 41:991-1001. [PMID: 23052976 DOI: 10.1007/s00249-012-0862-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 09/04/2012] [Accepted: 09/07/2012] [Indexed: 06/01/2023]
Abstract
Protein inhibitors that shift the thermodynamic equilibrium towards a denatured state escape, in general, the straightforward framework of competitive or allosteric inhibitors. The equilibrium properties of peptides which compete with the folding, or more precisely destabilize the native state, of the human immunodeficiency virus (HIV)-1 protease monomer are studied within a structure-based model. The effect of peptides that disrupt the hydrophobic core of the protein can still be summarized in terms of an inhibition constant, which depends on the thermal stability of the protein. The state of the protein denatured by such a peptide is more structured than its intrinsic denatured state, but displays the same degree of compactness. Peptides that target less buried regions of the protein are less efficient and display a more complex thermodynamics that cannot be captured in a simple way.
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Affiliation(s)
- S Kimura
- Department of Physics, University of Milano, via Celoria 16, 20133 Milan, Italy
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46
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Sayer JM, Aniana A, Louis JM. Mechanism of dissociative inhibition of HIV protease and its autoprocessing from a precursor. J Mol Biol 2012; 422:230-44. [PMID: 22659320 PMCID: PMC3418415 DOI: 10.1016/j.jmb.2012.05.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 05/15/2012] [Accepted: 05/15/2012] [Indexed: 11/17/2022]
Abstract
Dimerization is indispensible for release of the human immunodeficiency virus protease (PR) from its precursor (Gag-Pol) and ensuing mature-like catalytic activity that is crucial for virus maturation. We show that a single-chain Fv fragment (scFv) of a previously reported monoclonal antibody (mAb1696), which recognizes the N-terminus of PR, dissociates a dimeric mature D25N PR mutant with an enhanced dimer dissociation constant (K(d)) in the sub-micromolar range to form predominantly a monomer-scFv complex at a 1:1 ratio, along with small (5-10%) amounts of a dimer-scFv complex. Enzyme kinetics indicate a mixed mechanism of inhibition of the wild-type PR, which exhibits a K(d)<10nM, with effects both on K(m) and k(cat) at an scFv-to-PR ratio of 10:1. ScFv binds to the N-terminal peptide P(1)QITLW(6) of PR and to PR monomers with dissociation constants of ≤30 nM and ~100 nM, respectively. Consistent with an ~400-fold increase in the dissociation of the antibody (K(Ab)) on even addition of an acetyl group to P(1) of the peptide, the antibody fails to inhibit N-terminal autoprocessing of the PR from a model precursor (at ~5 μM). However, subsequent to this cleavage, it sequesters the PR, thus blocking autoprocessing at its C-terminus. A second monoclonal antibody [PRM1 (human monoclonal antibody to PR)], which recognizes part of the flap region (residues 41-47) of the mature PR and its precursor, does not inhibit autoprocessing and ensuing catalytic activity. However, its failure to recognize drug-resistant clinical mutants of PR may be beneficial to monitor the selection of mutations in this region under drug pressure.
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Affiliation(s)
| | | | - John M. Louis
- Corresponding author: John M. Louis, Building 5, Room B2-29, LCP, NIDDK, NIH, Bethesda, MD 20892-0520, Tel. 301 594-3122; Fax. 301 480-4001;
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47
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Yang H, Nkeze J, Zhao RY. Effects of HIV-1 protease on cellular functions and their potential applications in antiretroviral therapy. Cell Biosci 2012; 2:32. [PMID: 22971934 PMCID: PMC3490751 DOI: 10.1186/2045-3701-2-32] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 08/31/2012] [Indexed: 11/10/2022] Open
Abstract
Human Immunodeficiency Virus Type 1 (HIV-1) protease inhibitors (PIs) are the most potent class of drugs in antiretroviral therapies. However, viral drug resistance to PIs could emerge rapidly thus reducing the effectiveness of those drugs. Of note, all current FDA-approved PIs are competitive inhibitors, i.e., inhibitors that compete with substrates for the active enzymatic site. This common inhibitory approach increases the likelihood of developing drug resistant HIV-1 strains that are resistant to many or all current PIs. Hence, new PIs that move away from the current target of the active enzymatic site are needed. Specifically, allosteric inhibitors, inhibitors that prohibit PR enzymatic activities through non-competitive binding to PR, should be sought. Another common feature of current PIs is they were all developed based on the structure-based design. Drugs derived from a structure-based strategy may generate target specific and potent inhibitors. However, this type of drug design can only target one site at a time and drugs discovered by this method are often associated with strong side effects such as cellular toxicity, limiting its number of target choices, efficacy, and applicability. In contrast, a cell-based system may provide a useful alternative strategy that can overcome many of the inherited shortcomings associated with structure-based drug designs. For example, allosteric PIs can be sought using a cell-based system without considering the site or mechanism of inhibition. In addition, a cell-based system can eliminate those PIs that have strong cytotoxic effect. Most importantly, a simple, economical, and easy-to-maintained eukaryotic cellular system such as yeast will allow us to search for potential PIs in a large-scaled high throughput screening (HTS) system, thus increasing the chances of success. Based on our many years of experience in using fission yeast as a model system to study HIV-1 Vpr, we propose the use of fission yeast as a possible surrogate system to study the effects of HIV-1 protease on cellular functions and to explore its utility as a HTS system to search for new PIs to battle HIV-1 resistant strains.
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Affiliation(s)
- Hailiu Yang
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA.
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48
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Rout MK, Reddy JG, Phillips M, Hosur RV. Single point mutation induced alterations in the equilibrium structural transitions on the folding landscape of HIV-1 protease. J Biomol Struct Dyn 2012; 31:684-93. [PMID: 22909351 DOI: 10.1080/07391102.2012.707459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Equilibrium folding-unfolding transitions are hard to study in HIV-1 protease (PR) because of its autolytic properties. Further, the protease exhibits many tolerant point mutations some of which also impart drug resistance to the protein. It is conceivable that the mutations affect protein's function by altering its folding characteristics; these would clearly depend on the nature of the mutations themselves. In this background, we report here NMR studies on the effects of D25 N mutation, which removes one negative charge from the protein at the active site, on the equilibrium folding behaviour of PR starting from its acetic acid denatured state. It is observed that in PRD25N two slowly exchanging conformations are present at the N-terminal. One of them is similar to that of PR. Though the conformational and dynamics preferences of PR and PRD25N are fairly similar in 9 M acetic acid, they seem to undergo different folding transitions when acetic acid concentration is reduced. The differences are seen in the active site, in the flap, and in the hinge of the flap regions. The present study suggests that such differences, though different in detail, would occur for other mutations as well, and also for different initial denatured states. These would have significant regulatory implications for the efficacy of protease function.
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Affiliation(s)
- Manoj Kumar Rout
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai, 400005, India
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49
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Dufau L, Marques Ressurreição AS, Fanelli R, Kihal N, Vidu A, Milcent T, Soulier JL, Rodrigo J, Desvergne A, Leblanc K, Bernadat G, Crousse B, Reboud-Ravaux M, Ongeri S. Carbonylhydrazide-based molecular tongs inhibit wild-type and mutated HIV-1 protease dimerization. J Med Chem 2012; 55:6762-75. [PMID: 22800535 DOI: 10.1021/jm300181j] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have designed and synthesized new molecular tongs based on a rigid naphthalene scaffold and evaluated their antidimer activity on HIV-1 protease (PR). We inserted carbonylhydrazide and oligohydrazide (azatide) fragments into their peptidomimetic arms to reduce hydrophobicity and increase metabolic stability. These fragments are designed to disrupt the protein-protein interactions by reproducing the hydrogen bond pattern found in the antiparallel β-sheet formed between the N- and C-ends of the two monomers in the native PR. Kinetic analyses and fluorescent probe binding studies showed that several molecular tongs can inhibit PR dimerization. The best nonpeptidic molecular tongs to date were obtained with an inhibition constant K(id) of 50 nM for PR and 80 nM for the multimutated protease ANAM-11. The PR inhibition was selective, the aspartic proteases renin and pepsin were not inhibited.
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Affiliation(s)
- Laure Dufau
- UMR-CNRS 8076, Molécules Fluorées et Chimie Médicinale, LabEx LERMIT, Faculté de Pharmacie, Université Paris-Sud 11, 5 rue J. B. Clément, 92296 Châtenay-Malabry Cedex, France
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50
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Agniswamy J, Sayer JM, Weber IT, Louis JM. Terminal interface conformations modulate dimer stability prior to amino terminal autoprocessing of HIV-1 protease. Biochemistry 2012; 51:1041-50. [PMID: 22242794 PMCID: PMC3287067 DOI: 10.1021/bi201809s] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The HIV-1 protease (PR) mediates its own release (autoprocessing) from the polyprotein precursor, Gag-Pol, flanked by the transframe region (TFR) and reverse transcriptase at its N- and C-termini, respectively. Autoprocessing at the N-terminus of PR mediates stable dimer formation essential for catalytic activity, leading to the formation of infectious virus. An antiparallel β-sheet interface formed by the four N- and C-terminal residues of each subunit is important for dimer stability. Here, we present the first high-resolution crystal structures of model protease precursor-clinical inhibitor (PI darunavir or saquinavir) complexes, revealing varying conformations of the N-terminal flanking (S(-4)FNF(-1)) and interface residues (P(1)QIT(4)). A 180° rotation of the T(4)-L(5) peptide bond is accompanied by a new Q(2)-L(5) hydrogen bond and complete disengagement of PQIT from the β-sheet dimer interface, which may be a feature for intramolecular autoprocessing. This result is consistent with drastically lower thermal stability by 14-20 °C of PI complexes of precursors and the mature PR lacking its PQIT residues (by 18.3 °C). Similar to the TFR-PR precursor, this deletion also results in a darunavir dissociation constant (2 × 10(4))-fold higher and a markedly increased dimer dissociation constant relative to the mature PR. The terminal β-sheet perturbations of the dimeric structure likely account for the drastically poorer inhibition of autoprocessing of TFR-PR relative to the mature PR, even though significant differences in active site-PI interactions in these structures were not observed. The novel conformations of the dimer interface may be exploited to target selectively the protease precursor prior to its N-terminal cleavage.
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Affiliation(s)
- Johnson Agniswamy
- Department of Biology, Molecular Basis of Disease Program, Georgia State University, Atlanta, GA30303
| | - Jane M. Sayer
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, DHHS, Bethesda, Maryland 20892
| | - Irene T. Weber
- Department of Biology, Molecular Basis of Disease Program, Georgia State University, Atlanta, GA30303
| | - John M. Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, DHHS, Bethesda, Maryland 20892
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