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Sheik Ismail Z, Worth R, Mosebi S, Sayed Y. HIV Protease Hinge Region Insertions at Codon 38 Affect Enzyme Kinetics, Conformational Stability and Dynamics. Protein J 2023; 42:490-501. [PMID: 37421557 PMCID: PMC10480237 DOI: 10.1007/s10930-023-10132-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/23/2023] [Indexed: 07/10/2023]
Abstract
HIV-1 protease is essential for the production of mature, infectious virions and is a major target in antiretroviral therapy. We successfully purified a HIV-1 subtype C variant, L38↑N↑L- 4, containing an insertion of asparagine and leucine at position 38 without the four background mutations - K20R, E35D, R57K, V82I using a modified purification protocol. Isothermal titration calorimetry indicated that 50% of the variant protease sample was in the active conformation compared to 62% of the wild type protease. The secondary structure composition of the variant protease was unaffected by the double insertion. The specific activity and kcat values of the variant protease were approximately 50% lower than the wild type protease values. The variant protease also exhibited a 1.6-fold increase in kcat/KM when compared to the wild type protease. Differential scanning calorimetry showed a 5 °C increase in Tm of the variant protease, indicating the variant was more stable than the wild type. Molecular dynamics simulations indicated the variant was more stable and compact than the wild type protease. A 3-4% increase in the flexibility of the hinge regions of the variant protease was observed. In addition, increased flexibility of the flaps, cantilever and fulcrum regions of the variant protease B chain was observed. The variant protease sampled only the closed flap conformation indicating a potential mechanism for drug resistance. The present study highlights the direct impact of a double amino acid insertion in hinge region on enzyme kinetics, conformational stability and dynamics of an HIV-1 subtype C variant protease.
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Affiliation(s)
- Zaahida Sheik Ismail
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of Witwatersrand, Johannesburg, 2050, South Africa
| | - Roland Worth
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of Witwatersrand, Johannesburg, 2050, South Africa
| | - Salerwe Mosebi
- College of Agriculture & Environmental Sciences, School of Agriculture and Life Sciences, Department of Life and Consumer Sciences, UNISA, Pretoria, South Africa
| | - Yasien Sayed
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of Witwatersrand, Johannesburg, 2050, South Africa.
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Khade PM, Scaramozzino D, Kumar A, Lacidogna G, Carpinteri A, Jernigan RL. hdANM: a new comprehensive dynamics model for protein hinges. Biophys J 2021; 120:4955-4965. [PMID: 34687719 PMCID: PMC8633836 DOI: 10.1016/j.bpj.2021.10.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 09/22/2021] [Accepted: 10/18/2021] [Indexed: 01/03/2023] Open
Abstract
Hinge motions are essential for many protein functions, and their dynamics are important to understand underlying biological mechanisms. The ways that these motions are represented by various computational methods differ significantly. By focusing on a specific class of motion, we have developed a new hinge-domain anisotropic network model (hdANM) that is based on the prior identification of flexible hinges and rigid domains in the protein structure and the subsequent generation of global hinge motions. This yields a set of motions in which the relative translations and rotations of the rigid domains are modulated and controlled by the deformation of the flexible hinges, leading to a more restricted, specific view of these motions. hdANM is the first model, to our knowledge, that combines information about protein hinges and domains to model the characteristic hinge motions of a protein. The motions predicted with this new elastic network model provide important conceptual advantages for understanding the underlying biological mechanisms. As a matter of fact, the generated hinge movements are found to resemble the expected mechanisms required for the biological functions of diverse proteins. Another advantage of this model is that the domain-level coarse graining makes it significantly more computationally efficient, enabling the generation of hinge motions within even the largest molecular assemblies, such as those from cryo-electron microscopy. hdANM is also comprehensive as it can perform in the same way as the well-known protein dynamics models (anisotropic network model, rotations-translations of blocks, and nonlinear rigid block normal mode analysis), depending on the definition of flexible and rigid parts in the protein structure and on whether the motions are extrapolated in a linear or nonlinear fashion. Furthermore, our results indicate that hdANM produces more realistic motions as compared to the anisotropic network model. hdANM is an open-source software, freely available, and hosted on a user-friendly website.
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Affiliation(s)
- Pranav M Khade
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa
| | - Domenico Scaramozzino
- Department of Structural, Geotechnical, and Building Engineering, Politecnico di Torino, Torino, Italy
| | - Ambuj Kumar
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa
| | - Giuseppe Lacidogna
- Department of Structural, Geotechnical, and Building Engineering, Politecnico di Torino, Torino, Italy
| | - Alberto Carpinteri
- Department of Structural, Geotechnical, and Building Engineering, Politecnico di Torino, Torino, Italy
| | - Robert L Jernigan
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa.
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Lawal MM, Sanusi ZK, Govender T, Maguire GE, Honarparvar B, Kruger HG. From Recognition to Reaction Mechanism: An Overview on the Interactions between HIV-1 Protease and its Natural Targets. Curr Med Chem 2020; 27:2514-2549. [DOI: 10.2174/0929867325666181113122900] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 11/04/2018] [Accepted: 11/07/2018] [Indexed: 12/28/2022]
Abstract
Current investigations on the Human Immunodeficiency Virus Protease (HIV-1
PR) as a druggable target towards the treatment of AIDS require an update to facilitate further
development of promising inhibitors with improved inhibitory activities. For the past two
decades, up to 100 scholarly reports appeared annually on the inhibition and catalytic mechanism
of HIV-1 PR. A fundamental literature review on the prerequisite of HIV-1 PR action
leading to the release of the infectious virion is absent. Herein, recent advances (both computationally
and experimentally) on the recognition mode and reaction mechanism of HIV-1 PR
involving its natural targets are provided. This review features more than 80 articles from
reputable journals. Recognition of the natural Gag and Gag-Pol cleavage junctions by this
enzyme and its mutant analogs was first addressed. Thereafter, a comprehensive dissect of
the enzymatic mechanism of HIV-1 PR on its natural polypeptide sequences from literature
was put together. In addition, we highlighted ongoing research topics in which in silico
methods could be harnessed to provide deeper insights into the catalytic mechanism of the
HIV-1 protease in the presence of its natural substrates at the molecular level. Understanding
the recognition and catalytic mechanism of HIV-1 PR leading to the release of an infective
virion, which advertently affects the immune system, will assist in designing mechanismbased
inhibitors with improved bioactivity.
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Affiliation(s)
- Monsurat M. Lawal
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban 4041, South Africa
| | - Zainab K. Sanusi
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban 4041, South Africa
| | - Thavendran Govender
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban 4041, South Africa
| | - Glenn E.M. Maguire
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban 4041, South Africa
| | - Bahareh Honarparvar
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban 4041, South Africa
| | - Hendrik G. Kruger
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban 4041, South Africa
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Khade PM, Kumar A, Jernigan RL. Characterizing and Predicting Protein Hinges for Mechanistic Insight. J Mol Biol 2019; 432:508-522. [PMID: 31786268 DOI: 10.1016/j.jmb.2019.11.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 11/01/2019] [Accepted: 11/15/2019] [Indexed: 12/21/2022]
Abstract
The functioning of proteins requires highly specific dynamics, which depend critically on the details of how amino acids are packed. Hinge motions are the most common type of large motion, typified by the opening and closing of enzymes around their substrates. The packing and geometries of residues are characterized here by graph theory. This characterization is sufficient to enable reliable hinge predictions from a single static structure, and notably, this can be from either the open or the closed form of a structure. This new method to identify hinges within protein structures is called PACKMAN. The predicted hinges are validated by using permutation tests on B-factors. Hinge prediction results are compared against lists of manually curated hinge residues, and the results suggest that PACKMAN is robust enough to reproduce the known conformational changes and is able to predict hinge regions equally well from either the open or the closed forms of a protein. A group of 167 protein pairs with open and closed structures has been investigated Examples are shown for several additional proteins, including Zika virus nonstructured (NS) proteins where there are 6 hinge regions in the NS5 protein, 5 hinge regions in the NS2B bound in the NS3 protease complex and 5 hinges in the NS3- helicase protein. Results obtained from this method can be important for generating conformational ensembles of protein targets for drug design. PACKMAN is freely accessible at (https://PACKMAN.bb.iastate.edu/).
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Affiliation(s)
- Pranav M Khade
- Bioinformatics and Computational Biology Program, Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
| | - Ambuj Kumar
- Bioinformatics and Computational Biology Program, Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
| | - Robert L Jernigan
- Bioinformatics and Computational Biology Program, Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, 50011, USA.
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Sumbul F, Acuner-Ozbabacan SE, Haliloglu T. Allosteric Dynamic Control of Binding. Biophys J 2015; 109:1190-201. [PMID: 26338442 DOI: 10.1016/j.bpj.2015.08.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 08/12/2015] [Accepted: 08/13/2015] [Indexed: 12/31/2022] Open
Abstract
Proteins have a highly dynamic nature and there is a complex interrelation between their structural dynamics and binding behavior. By assuming various conformational ensembles, they perform both local and global fluctuations to interact with other proteins in a dynamic infrastructure adapted to functional motion. Here, we show that there is a significant association between allosteric mutations, which lead to high-binding-affinity changes, and the hinge positions of global modes, as revealed by a large-scale statistical analysis of data in the Structural Kinetic and Energetic Database of Mutant Protein Interactions (SKEMPI). We further examined the mechanism of allosteric dynamics by conducting studies on human growth hormone (hGH) and pyrin domain (PYD), and the results show how mutations at the hinge regions could allosterically affect the binding-site dynamics or induce alternative binding modes by modifying the ensemble of accessible conformations. The long-range dissemination of perturbations in local chemistry or physical interactions through an impact on global dynamics can restore the allosteric dynamics. Our findings suggest a mechanism for the coupling of structural dynamics to the modulation of protein interactions, which remains a critical phenomenon in understanding the effect of mutations that lead to functional changes in proteins.
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Affiliation(s)
- Fidan Sumbul
- Department of Chemical Engineering and Polymer Research Center, Bogazici University, Istanbul, Turkey
| | | | - Turkan Haliloglu
- Department of Chemical Engineering and Polymer Research Center, Bogazici University, Istanbul, Turkey.
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Haliloglu T, Bahar I. Adaptability of protein structures to enable functional interactions and evolutionary implications. Curr Opin Struct Biol 2015; 35:17-23. [PMID: 26254902 DOI: 10.1016/j.sbi.2015.07.007] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 07/15/2015] [Accepted: 07/20/2015] [Indexed: 12/21/2022]
Abstract
Several studies in recent years have drawn attention to the ability of proteins to adapt to intermolecular interactions by conformational changes along structure-encoded collective modes of motions. These so-called soft modes, primarily driven by entropic effects, facilitate, if not enable, functional interactions. They represent excursions on the conformational space along principal low-ascent directions/paths away from the original free energy minimum, and they are accessible to the protein even before protein-protein/ligand interactions. An emerging concept from these studies is the evolution of structures or modular domains to favor such modes of motion that will be recruited or integrated for enabling functional interactions. Structural dynamics, including the allosteric switches in conformation that are often stabilized upon formation of complexes and multimeric assemblies, emerge as key properties that are evolutionarily maintained to accomplish biological activities, consistent with the paradigm sequence→structure→dynamics→function where 'dynamics' bridges structure and function.
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Affiliation(s)
- Turkan Haliloglu
- Department of Chemical Engineering and Polymer Research Center, and Center for Life Sciences and Technologies, Bogazici University, 34342 Istanbul, Turkey; Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Ivet Bahar
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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