1
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Sanusi ZK, Lawal MM, Gupta PL, Govender T, Baijnath S, Naicker T, Maguire GEM, Honarparvar B, Roitberg AE, Kruger HG. Exploring the concerted mechanistic pathway for HIV-1 PR-substrate revealed by umbrella sampling simulation. J Biomol Struct Dyn 2020; 40:1736-1747. [PMID: 33073714 DOI: 10.1080/07391102.2020.1832578] [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: 10/23/2022]
Abstract
HIV-1 protease (HIV-1 PR) is an essential enzyme for the replication process of its virus, and therefore considered an important target for the development of drugs against the acquired immunodeficiency syndrome (AIDS). Our previous study shows that the catalytic mechanism of subtype B/C-SA HIV-1 PR follows a one-step concerted acyclic hydrolysis reaction process using a two-layered ONIOM B3LYP/6-31++G(d,p) method. This present work is aimed at exploring the proposed mechanism of the proteolysis catalyzed by HIV-1 PR and to ensure our proposed mechanism is not an artefact of a single theoretical technique. Hence, we present umbrella sampling method that is suitable for calculating potential mean force (PMF) for non-covalent ligand/substrate-enzyme association/dissociation interactions which provide thermodynamic details for molecular recognition. The free activation energy results were computed in terms of PMF analysis within the hybrid QM(DFTB)/MM approach. The theoretical findings suggest that the proposed mechanism corresponds in principle with experimental data. Given our observations, we suggest that the QM/MM MD method can be used as a reliable computational technique to rationalize lead compounds against specific targets such as the HIV-1 protease.
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Affiliation(s)
- Zainab K Sanusi
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Monsurat M Lawal
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Pancham Lal Gupta
- Department of Chemistry, University of Florida, Gainesville, Florida, USA
| | | | - Sooraj Baijnath
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Tricia Naicker
- 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
| | - Adrian E Roitberg
- Department of Chemistry, University of Florida, Gainesville, Florida, USA
| | - Hendrik G Kruger
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
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2
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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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3
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Cheuka PM, Dziwornu G, Okombo J, Chibale K. Plasmepsin Inhibitors in Antimalarial Drug Discovery: Medicinal Chemistry and Target Validation (2000 to Present). J Med Chem 2020; 63:4445-4467. [PMID: 31913032 DOI: 10.1021/acs.jmedchem.9b01622] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Plasmepsins represent novel antimalarial drug targets. However, plasmepsin-based antimalarial drug discovery efforts in the past 2 decades have generally suffered some drawbacks including lack of translatability of target inhibition to potent parasite inhibition in vitro and in vivo as well as poor selectivity over the related human aspartic proteases. Most studies reported in this period have over-relied on the use of hemoglobinase plasmepsins I-IV (particularly I and II) as targets for the new inhibitors even though these are known to be nonessential at the asexual stage of parasite development. Therefore, future antimalarial drug discovery efforts seeking to identify plasmepsin inhibitors should focus on incorporating non-hemoglobinase plasmepsins such as V, IX, and X in their screening in order to maximize chances of success. Additionally, there is need to go beyond just target enzymatic activity profiling to establishing cellular activity, physicochemical as well as drug metabolism and pharmacokinetics properties and finally in vivo proof-of-concept while ensuring selectivity over related human host proteases.
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Affiliation(s)
- Peter Mubanga Cheuka
- Department of Chemistry, University of Zambia, Great East Road Campus, P.O. Box 32379, Lusaka, Zambia
| | - Godwin Dziwornu
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - John Okombo
- Department of Microbiology and Immunology, Columbia University, 701 West 168th Street, New York, New York 10032, United States
| | - Kelly Chibale
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa.,Drug Discovery and Development Centre (H3D), Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa.,Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa.,South African Medical Research Council Drug Discovery and Development Research Unit, University of Cape Town, Rondebosch 7701, South Africa
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4
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Sanusi ZK, Lawal MM, Govender T, Baijnath S, Naicker T, Maguire GEM, Honarparvar B, Kruger HG. Concerted hydrolysis mechanism of HIV-1 natural substrate against subtypes B and C-SA PR: insight through molecular dynamics and hybrid QM/MM studies. Phys Chem Chem Phys 2020; 22:2530-2539. [PMID: 31942584 DOI: 10.1039/c9cp05639d] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
It is well known that understanding the catalytic mechanism of HIV-1 PR is the rationale on which its inhibitors were developed; therefore, a better understanding of the mechanism of natural substrate hydrolysis is important. Herein, the reaction mechanism of HIV-1 natural substrates with subtypes B and common mutant in South Africa (subtype C-SA) protease were studied through transition state modelling, using a general acid-general base (GA-GB) one-step concerted process. The activation free energies of enzyme-substrate complexes were compared based on their rate of hydrolysis using a two-layered ONIOM (B3LYP/6-31++G(d,p):AMBER) method. We expanded our computational model to obtain a better understanding of the mechanism of hydrolysis as well as how the enzyme recognises or chooses the cleavage site of the scissile bonds. Using this model, a potential substrate-based inhibitor could be developed with better potency. The calculated activation energies of natural substrates in our previous study correlated well with experimental data. A similar trend was observed for the Gag and Gag-Pol natural substrates in the present work for both enzyme complexes except for the PR-RT substrate. Natural bond orbital (NBO) analysis was also applied to determine the extent of charge transfer within the QM part of both enzymes considered and the PR-RT natural substrate. The result of this study shows that the method can be utilized as a dependable computational technique to rationalize lead compounds against specific targets.
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Affiliation(s)
- Zainab K Sanusi
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban 4041, South Africa.
| | - Monsurat M Lawal
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban 4041, South Africa.
| | | | - Sooraj Baijnath
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban 4041, South Africa.
| | - Tricia Naicker
- 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. and School of Chemistry and Physics, 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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5
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Mehra R, Dehury B, Kepp KP. Cryo-temperature effects on membrane protein structure and dynamics. Phys Chem Chem Phys 2020; 22:5427-5438. [DOI: 10.1039/c9cp06723j] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Cryo-electron structures revolutionize biology, yet cooling effects are unclear. Using a simulation protocol of hot, cold, and rapidly cooled γ-secretase we identify cryo-contraction and modes relevant to Aβ production and cryo-analysis in general.
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Affiliation(s)
- Rukmankesh Mehra
- DTU Chemistry
- Technical University of Denmark
- DK-2800 Kongens Lyngby
- Denmark
| | - Budheswar Dehury
- DTU Chemistry
- Technical University of Denmark
- DK-2800 Kongens Lyngby
- Denmark
| | - Kasper P. Kepp
- DTU Chemistry
- Technical University of Denmark
- DK-2800 Kongens Lyngby
- Denmark
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6
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Macrocycle modeling in ICM: benchmarking and evaluation in D3R Grand Challenge 4. J Comput Aided Mol Des 2019; 33:1057-1069. [DOI: 10.1007/s10822-019-00225-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Accepted: 09/17/2019] [Indexed: 01/07/2023]
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7
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Wiedmer L, Schärer C, Spiliotopoulos D, Hürzeler M, Śledź P, Caflisch A. Ligand retargeting by binding site analogy. Eur J Med Chem 2019; 175:107-113. [DOI: 10.1016/j.ejmech.2019.04.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 04/11/2019] [Accepted: 04/13/2019] [Indexed: 12/27/2022]
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8
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Aguayo‐Ortiz R, Guzmán‐Ocampo DC, Dominguez L. Toward the Characterization of DAPT Interactions with γ‐Secretase. ChemMedChem 2019; 14:1005-1010. [DOI: 10.1002/cmdc.201900106] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 03/26/2019] [Indexed: 01/08/2023]
Affiliation(s)
- Rodrigo Aguayo‐Ortiz
- Facultad de QuímicaDepartamento de FisicoquímicaUniversidad Nacional Autónoma de México Mexico City 04510 Mexico
| | - Dulce C. Guzmán‐Ocampo
- Facultad de QuímicaDepartamento de FisicoquímicaUniversidad Nacional Autónoma de México Mexico City 04510 Mexico
| | - Laura Dominguez
- Facultad de QuímicaDepartamento de FisicoquímicaUniversidad Nacional Autónoma de México Mexico City 04510 Mexico
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9
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Gueto-Tettay C, Martinez-Consuegra A, Pelaez-Bedoya L, Drosos-Ramirez JC. G-score: A function to solve the puzzle of modeling the protonation states of β-secretase binding pocket. J Mol Graph Model 2018; 85:1-12. [PMID: 30053756 DOI: 10.1016/j.jmgm.2018.07.008] [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: 05/17/2018] [Revised: 07/13/2018] [Accepted: 07/16/2018] [Indexed: 10/28/2022]
Abstract
The population density concept has emerged as a proposal for the analysis of molecular dynamics results, the key characteristic of population density is the evaluation of the simultaneous occurrence of a set of relevant parameters for a system. However, despite its statistical strength, selection of the tolerance level for the comparison of different models may appear as arbitrary. This work introduces the G-score, a function which summarizes and categorizes the results of population density analysis. Additionally, it incorporates parameters based on rmsd and dihedral angles, besides the protein-protein and protein-ligand interatomic distances conventionally used, which complement each other to provide a better description of the behavior of the system. These newly-proposed tools were applied to determine the most probable protonation state of the aspartic dyad of BACE1, Asp93 and Asp289, in the presence of three types of transition state inhibitors namely: reduced amides, tertiary carbinamines and hydroxyethylamines. The results show a full agreement between G-score values and population density charts, with the advantage of allowing a quick and direct comparison among all the considered models. We anticipate that the simplicity of calculating the parameters employed in this study will permit the extensive use of population density and the G-score for other molecular systems.
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Affiliation(s)
- Carlos Gueto-Tettay
- Grupo de Química Bioorgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Cartagena, Campus San Pablo, 130015, Colombia; Lund University, Faculty of Medicine, Department of Clinical Sciences Lund, Division of Infection Medicine, Lund, Sweden.
| | - Alejandro Martinez-Consuegra
- Grupo de Química Bioorgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Cartagena, Campus San Pablo, 130015, Colombia
| | - Luis Pelaez-Bedoya
- Grupo de Química Bioorgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Cartagena, Campus San Pablo, 130015, Colombia
| | - Juan Carlos Drosos-Ramirez
- Grupo de Química Bioorgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Cartagena, Campus San Pablo, 130015, Colombia.
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10
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Evaluation of an Allosteric BACE Inhibitor Peptide to Identify Mimetics that Can Interact with the Loop F Region of the Enzyme and Prevent APP Cleavage. J Mol Biol 2018; 430:1566-1576. [DOI: 10.1016/j.jmb.2018.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 04/03/2018] [Accepted: 04/03/2018] [Indexed: 12/14/2022]
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11
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Linkuvienė V, Talibov VO, Danielson UH, Matulis D. Introduction of Intrinsic Kinetics of Protein–Ligand Interactions and Their Implications for Drug Design. J Med Chem 2018; 61:2292-2302. [DOI: 10.1021/acs.jmedchem.7b01408] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Vaida Linkuvienė
- Department of Biothermodynamics and Drug Design, Institute of Biotechnology, Vilnius University, Saulėtekio 7, Vilnius, LT-10257, Lithuania
| | - Vladimir O. Talibov
- Department of Chemistry - BMC, Uppsala University, Box 576, Uppsala, SE-751 23, Sweden
| | - U. Helena Danielson
- Department of Chemistry - BMC, Uppsala University, Box 576, Uppsala, SE-751 23, Sweden
- Science for Life Laboratory, Uppsala University, Uppsala, SE-751 23, Sweden
| | - Daumantas Matulis
- Department of Biothermodynamics and Drug Design, Institute of Biotechnology, Vilnius University, Saulėtekio 7, Vilnius, LT-10257, Lithuania
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12
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Aguayo-Ortiz R, Chávez-García C, Straub JE, Dominguez L. Characterizing the structural ensemble of γ-secretase using a multiscale molecular dynamics approach. Chem Sci 2017; 8:5576-5584. [PMID: 28970936 PMCID: PMC5618787 DOI: 10.1039/c7sc00980a] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 06/05/2017] [Indexed: 11/21/2022] Open
Abstract
γ-Secretase is an intramembrane-cleaving aspartyl protease that plays an essential role in the processing of a variety of integral membrane proteins. Its role in the ultimate cleavage step in the processing of amyloid precursor protein to form amyloid-β (Aβ) peptide makes it an important therapeutic target in Alzheimer's disease research. Significant recent advances have been made in structural studies of this critical membrane protein complex. However, details of the mechanism of activation of the enzyme complex remain unclear. Using a multiscale computational modeling approach, combining multiple coarse-grained microsecond dynamic trajectories with all-atom models, the structure and two conformational states of the γ-secretase complex were evaluated. The transition between enzymatic state 1 and state 2 is shown to critically depend on the protonation states of the key catalytic residues Asp257 and Asp385 in the active site domain. The active site formation, related to our γ-secretase state 2, is observed to involve a concerted movement of four transmembrane helices from the catalytic subunit, resulting in the required localization of the catalytic residues. Global analysis of the structural ensemble of the enzyme complex was used to identify collective fluctuations important to the mechanism of substrate recognition and demonstrate that the corresponding fluctuations observed were uncorrelated with structural changes associated with enzyme activation. Overall, this computational study provides essential insight into the role of structure and dynamics in the activation and function of γ-secretase.
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Affiliation(s)
- Rodrigo Aguayo-Ortiz
- Departamento de Fisicoquímica , Facultad de Química , Universidad Nacional Autónoma de México , Mexico City , 04510 , Mexico .
| | - Cecilia Chávez-García
- Departamento de Fisicoquímica , Facultad de Química , Universidad Nacional Autónoma de México , Mexico City , 04510 , Mexico .
| | - John E Straub
- Department of Chemistry , Boston University , Boston , Massachusetts 02215 , USA
| | - Laura Dominguez
- Departamento de Fisicoquímica , Facultad de Química , Universidad Nacional Autónoma de México , Mexico City , 04510 , Mexico .
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13
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Qu S, Huang S, Pan X, Yang L, Mei H. Constructing Interconsistent, Reasonable, and Predictive Models for Both the Kinetic and Thermodynamic Properties of HIV-1 Protease Inhibitors. J Chem Inf Model 2016; 56:2061-2068. [PMID: 27624663 DOI: 10.1021/acs.jcim.6b00326] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Accumulated evidence suggests that the in vivo biological potency of a ligand is more strongly correlated with the binding/unbinding kinetics than the equilibrium thermodynamics of the protein-ligand interaction (PLI). However, the existing experimental and computational techniques are largely insufficient and limited in large-scale measurements or accurate predictions of the kinetic properties of PLI. In this work, elaborate efforts have been made to develop interconsistent, reasonable, and predictive models of the association rate constant (kon), dissociation rate constant (koff), and equilibrium dissociation constant (KD) of a series of HIV protease inhibitors with different structural skeletons. The results showed that nine Volsurf descriptors derived from water (OH2) and hydrophobic (DRY) probes are key molecular determinants for the kinetic and thermodynamic properties of HIV-1 protease inhibitors. To the best of our knowledge, this is the first time that interconsistent and reasonable models with strong prediction power have been established for both the kinetic and thermodynamic properties of HIV protease inhibitors.
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Affiliation(s)
- Sujun Qu
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Chongqing University , Chongqing 400044, China
| | - Shuheng Huang
- College of Bioengineering, Chongqing University , Chongqing 400044, China
| | - Xianchao Pan
- College of Bioengineering, Chongqing University , Chongqing 400044, China
| | - Li Yang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Chongqing University , Chongqing 400044, China.,College of Bioengineering, Chongqing University , Chongqing 400044, China
| | - Hu Mei
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Chongqing University , Chongqing 400044, China.,College of Bioengineering, Chongqing University , Chongqing 400044, China
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14
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Renaud JP, Chung CW, Danielson UH, Egner U, Hennig M, Hubbard RE, Nar H. Biophysics in drug discovery: impact, challenges and opportunities. Nat Rev Drug Discov 2016; 15:679-98. [PMID: 27516170 DOI: 10.1038/nrd.2016.123] [Citation(s) in RCA: 209] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Over the past 25 years, biophysical technologies such as X-ray crystallography, nuclear magnetic resonance spectroscopy, surface plasmon resonance spectroscopy and isothermal titration calorimetry have become key components of drug discovery platforms in many pharmaceutical companies and academic laboratories. There have been great improvements in the speed, sensitivity and range of possible measurements, providing high-resolution mechanistic, kinetic, thermodynamic and structural information on compound-target interactions. This Review provides a framework to understand this evolution by describing the key biophysical methods, the information they can provide and the ways in which they can be applied at different stages of the drug discovery process. We also discuss the challenges for current technologies and future opportunities to use biophysical methods to solve drug discovery problems.
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Affiliation(s)
- Jean-Paul Renaud
- NovAliX, Boulevard Sébastien Brant, 67405 Illkirch Cedex, France.,Institut de Génétique et Biologie Moléculaire et Cellulaire, CNRS UMR7104/INSERM U964/Université de Strasbourg, 1 rue Laurent Fries - BP10142, 67404 Illkirch Cedex, France.,RiboStruct, 15 rue Neuve, 67540 Ostwald, France
| | - Chun-Wa Chung
- GlaxoSmithKline R&D, Gunnels Wood Road, Stevenage, SG1 2NY, UK
| | - U Helena Danielson
- Department of Chemistry - BMC and Science for Life Laboratory, Drug Discovery &Development Platform, Uppsala University, SE-751 05 Uppsala, Sweden.,Beactica AB, Uppsala Business Park, 754 50 Uppsala, Sweden
| | - Ursula Egner
- Bayer Pharma AG, Müllerstrasse 178, 13353 Berlin, Germany
| | - Michael Hennig
- Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070 Basel, Switzerland.,leadXpro AG, PARK INNOVAARE, CH-5234 Villigen, Switzerland
| | - Roderick E Hubbard
- University of York, Heslington, York, YO10 5DD, UK.,Vernalis (R&D), Granta Park, Cambridge, CB21 6GB, UK
| | - Herbert Nar
- Boehringer Ingelheim GmbH &Co. KG, Birkendorfer Strasse 65, 88400 Biberach, Germany
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15
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Soares RO, Torres PHM, da Silva ML, Pascutti PG. Unraveling HIV protease flaps dynamics by Constant pH Molecular Dynamics simulations. J Struct Biol 2016; 195:216-226. [PMID: 27291071 DOI: 10.1016/j.jsb.2016.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 06/08/2016] [Accepted: 06/09/2016] [Indexed: 11/15/2022]
Abstract
The active site of HIV protease (HIV-PR) is covered by two flaps. These flaps are known to be essential for the catalytic activity of the HIV-PR, but their exact conformations at the different stages of the enzymatic pathway remain subject to debate. Understanding the correct functional dynamics of the flaps might aid the development of new HIV-PR inhibitors. It is known that, the HIV-PR catalytic efficiency is pH-dependent, likely due to the influence of processes such as charge transfer and protonation/deprotonation of ionizable residues. Several Molecular Dynamics (MD) simulations have reported information about the HIV-PR flaps. However, in MD simulations the protonation of a residue is fixed and thus it is not possible to study the correlation between conformation and protonation state. To address this shortcoming, this work attempts to capture, through Constant pH Molecular Dynamics (CpHMD), the conformations of the apo, substrate-bound and inhibitor-bound HIV-PR, which differ drastically in their flap arrangements. The results show that the HIV-PR flaps conformations are defined by the protonation of the catalytic residues Asp25/Asp25' and that these residues are sensitive to pH changes. This study suggests that the catalytic aspartates can modulate the opening of the active site and substrate binding.
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Affiliation(s)
- Rosemberg O Soares
- Instituto de Biofísica Carlos Chagas Filho (IBCCF), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil; Diretoria de Metrologia Aplicada às Ciências da Vida (DIMAV), Instituto Nacional de Metrologia Qualidade e Tecnologia (INMETRO), Xerém, Brazil.
| | - Pedro H M Torres
- Instituto de Biofísica Carlos Chagas Filho (IBCCF), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Manuela L da Silva
- Diretoria de Metrologia Aplicada às Ciências da Vida (DIMAV), Instituto Nacional de Metrologia Qualidade e Tecnologia (INMETRO), Xerém, Brazil
| | - Pedro G Pascutti
- Instituto de Biofísica Carlos Chagas Filho (IBCCF), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil; Diretoria de Metrologia Aplicada às Ciências da Vida (DIMAV), Instituto Nacional de Metrologia Qualidade e Tecnologia (INMETRO), Xerém, Brazil
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16
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Influence of surface charge, binding site residues and glycosylation on Thielavia terrestris cutinase biochemical characteristics. Appl Microbiol Biotechnol 2016; 100:4435-46. [PMID: 26758295 DOI: 10.1007/s00253-015-7254-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Revised: 09/13/2015] [Accepted: 12/12/2015] [Indexed: 02/06/2023]
Abstract
Cutinases are esterases of industrial importance for applications in recycling and surface modification of polyesters. The cutinase from Thielavia terrestris (TtC) is distinct in terms of its ability to retain its stability and activity in acidic pH. Stability and activity in acidic pHs are desirable for esterases as the pH of the reaction tends to go down with the generation of acid. The pH stability and activity are governed by the charged state of the residues involved in catalysis or in substrate binding. In this study, we performed the detailed structural and biochemical characterization of TtC coupled with surface charge analysis to understand its acidic tolerance. The stability of TtC in acidic pH was rationalized by evaluating the contribution of charge interactions to the Gibbs free energy of unfolding at varying pHs. The activity of TtC was found to be limited by substrate binding affinity, which is a function of the surface charge. Additionally, the presence of glycosylation affects the biochemical characteristics of TtC owing to steric interactions with residues involved in substrate binding.
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Conformational Dynamics and Binding Free Energies of Inhibitors of BACE-1: From the Perspective of Protonation Equilibria. PLoS Comput Biol 2015; 11:e1004341. [PMID: 26506513 PMCID: PMC4623973 DOI: 10.1371/journal.pcbi.1004341] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 05/17/2015] [Indexed: 11/19/2022] Open
Abstract
BACE-1 is the β-secretase responsible for the initial amyloidogenesis in Alzheimer’s disease, catalyzing hydrolytic cleavage of substrate in a pH-sensitive manner. The catalytic mechanism of BACE-1 requires water-mediated proton transfer from aspartyl dyad to the substrate, as well as structural flexibility in the flap region. Thus, the coupling of protonation and conformational equilibria is essential to a full in silico characterization of BACE-1. In this work, we perform constant pH replica exchange molecular dynamics simulations on both apo BACE-1 and five BACE-1-inhibitor complexes to examine the effect of pH on dynamics and inhibitor binding properties of BACE-1. In our simulations, we find that solution pH controls the conformational flexibility of apo BACE-1, whereas bound inhibitors largely limit the motions of the holo enzyme at all levels of pH. The microscopic pKa values of titratable residues in BACE-1 including its aspartyl dyad are computed and compared between apo and inhibitor-bound states. Changes in protonation between the apo and holo forms suggest a thermodynamic linkage between binding of inhibitors and protons localized at the dyad. Utilizing our recently developed computational protocol applying the binding polynomial formalism to the constant pH molecular dynamics (CpHMD) framework, we are able to obtain the pH-dependent binding free energy profiles for various BACE-1-inhibitor complexes. Our results highlight the importance of correctly addressing the binding-induced protonation changes in protein-ligand systems where binding accompanies a net proton transfer. This work comprises the first application of our CpHMD-based free energy computational method to protein-ligand complexes and illustrates the value of CpHMD as an all-purpose tool for obtaining pH-dependent dynamics and binding free energies of biological systems. Formation of insoluble amyloid plaques in the vascular and hippocampal areas of the brain characterizes Alzheimer’s disease, a devastating neurodegenerative disorder causing dementia. Site-specific hydrolytic catalysis of β-secretase, or BACE-1, is responsible for production of oligomerative amyloid β-peptide. As the catalytic activity of BACE-1 is pH-dependent and its structural dynamics are intrinsic to the catalysis, we examine the dependence of dynamics of BACE-1 on solution pH and its implications on the catalytic mechanism of BACE-1. Also, we highlight the importance of accurate description of protonation states of the titratable groups in computer-aided drug discovery targeting BACE-1. We hope the understanding of pH dependence of the dynamics and inhibitor binding properties of BACE-1 will aid the structure-based inhibitor design efforts against Alzheimer’s disease.
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Yuan H, Myers SJ, Wells G, Nicholson KL, Swanger SA, Lyuboslavsky P, Tahirovic YA, Menaldino DS, Ganesh T, Wilson LJ, Liotta DC, Snyder JP, Traynelis SF. Context-dependent GluN2B-selective inhibitors of NMDA receptor function are neuroprotective with minimal side effects. Neuron 2015; 85:1305-1318. [PMID: 25728572 DOI: 10.1016/j.neuron.2015.02.008] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 01/12/2015] [Accepted: 01/29/2015] [Indexed: 01/09/2023]
Abstract
Stroke remains a significant problem despite decades of work on neuroprotective strategies. NMDA receptor (NMDAR) antagonists are neuroprotective in preclinical models, but have been clinically unsuccessful, in part due to side effects. Here we describe a prototypical GluN2B-selective antagonist with an IC50 value that is 10-fold more potent at acidic pH 6.9 associated with ischemic tissue compared to pH 7.6, a value close to the pH in healthy brain tissue. This should maximize neuroprotection in ischemic tissue while minimizing on-target side effects associated with NMDAR blockade in noninjured brain regions. We have determined the mechanism underlying pH-dependent inhibition and demonstrate the utility of this approach in vivo. We also identify dicarboxylate dimers as a novel proton sensor in proteins. These results provide insight into the molecular basis of pH-dependent neuroprotective NMDAR block, which could be beneficial in a wide range of neurological insults associated with tissue acidification.
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Affiliation(s)
- Hongjie Yuan
- Department of Pharmacology, Emory University, Atlanta, GA 30322 USA
| | - Scott J Myers
- Department of Pharmacology, Emory University, Atlanta, GA 30322 USA
| | - Gordon Wells
- Department of Chemistry, Emory University, Atlanta, GA 30322 USA
| | - Katherine L Nicholson
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298 USA.,Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA 23298 USA
| | - Sharon A Swanger
- Department of Pharmacology, Emory University, Atlanta, GA 30322 USA
| | | | | | | | - Thota Ganesh
- Department of Pharmacology, Emory University, Atlanta, GA 30322 USA
| | | | - Dennis C Liotta
- Department of Chemistry, Emory University, Atlanta, GA 30322 USA
| | - James P Snyder
- Department of Chemistry, Emory University, Atlanta, GA 30322 USA
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Domínguez JL, Fernández-Nieto F, Castro M, Catto M, Paleo MR, Porto S, Sardina FJ, Brea JM, Carotti A, Villaverde MC, Sussman F. Computer-aided structure-based design of multitarget leads for Alzheimer's disease. J Chem Inf Model 2014; 55:135-48. [PMID: 25483751 DOI: 10.1021/ci500555g] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Alzheimer's disease is a neurodegenerative pathology with unmet clinical needs. A highly desirable approach to this syndrome would be to find a single lead that could bind to some or all of the selected biomolecules that participate in the amyloid cascade, the most accepted route for Alzheimer disease genesis. In order to circumvent the challenge posed by the sizable differences in the binding sites of the molecular targets, we propose a computer-assisted protocol based on a pharmacophore and a set of required interactions with the targets that allows for the automated screening of candidates. We used a combination of docking and molecular dynamics protocols in order to discard nonbinders, optimize the best candidates, and provide a rationale for their potential as inhibitors. To provide a proof of concept, we proceeded to screen the literature and databases, a task that allowed us to identify a set of carbazole-containing compounds that initially showed affinity only for the cholinergic targets in our experimental assays. Two cycles of design based on our protocol led to a new set of analogues that were synthesized and assayed. The assay results revealed that the designed inhibitors had improved affinities for BACE-1 by more than 3 orders of magnitude and also displayed amyloid aggregation inhibition and affinity for AChE and BuChE, a result that led us to a group of multitarget amyloid cascade inhibitors that also could have a positive effect at the cholinergic level.
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Affiliation(s)
- José L Domínguez
- Departamento de Química Orgánica, Facultad de Química, Universidad de Santiago de Compostela , 15782 Santiago de Compostela, Spain
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Lakshmi B, Sinduja C, Archunan G, Srinivasan N. Ramachandran analysis of conserved glycyl residues in homologous proteins of known structure. Protein Sci 2014; 23:843-50. [PMID: 24687432 DOI: 10.1002/pro.2468] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 03/16/2014] [Accepted: 03/25/2014] [Indexed: 11/10/2022]
Abstract
High conservation of glycyl residues in homologous proteins is fairly frequent. It is commonly understood that glycine tends to be highly conserved either because of its unique Ramachandran angles or to avoid steric clash that would arise with a larger side chain. Using a database of aligned 3D structures of homologous proteins we identified conserved Gly in 288 alignment positions from 85 families. Ninety-six of these alignment positions correspond to conserved Gly residue with (φ, ψ) values allowed for non-glycyl residues. Reasons for this observation were investigated by in-silico mutation of these glycyl residues to Ala. We found in 94% of the cases a short contact exists between the C(β) atom of the introduced Ala with the atoms which are often distant in the primary structure. This suggests the lack of space even for a short side chain thereby explaining high conservation of glycyl residues even when they adopt (φ, ψ) values allowed for Ala. In 189 alignment positions, the conserved glycyl residues adopt (φ, ψ) values which are disallowed for Ala. In-silico mutation of these Gly residues to Ala almost always results in steric hindrance involving C(β) atom of Ala as one would expect by comparing Ramachandran maps for Ala and Gly. Rare occurrence of the disallowed glycyl conformations even in ultrahigh resolution protein structures are accompanied by short contacts in the crystal structures and such disallowed conformations are not conserved in the homologues. These observations raise the doubt on the accuracy of such glycyl conformations in proteins.
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Affiliation(s)
- Balasubramanian Lakshmi
- Department of Animal Science, Bharathidasan University, Tiruchirappalli, 620024, Tamil Nadu, India; Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, Karnataka, India
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