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Estelle AB, George A, Barbar EJ, Zuckerman DM. Quantifying cooperative multisite binding in the hub protein LC8 through Bayesian inference. PLoS Comput Biol 2023; 19:e1011059. [PMID: 37083599 PMCID: PMC10155966 DOI: 10.1371/journal.pcbi.1011059] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 05/03/2023] [Accepted: 03/29/2023] [Indexed: 04/22/2023] Open
Abstract
Multistep protein-protein interactions underlie most biological processes, but their characterization through methods such as isothermal titration calorimetry (ITC) is largely confined to simple models that provide little information on the intermediate, individual steps. In this study, we primarily examine the essential hub protein LC8, a small dimer that binds disordered regions of 100+ client proteins in two symmetrical grooves at the dimer interface. Mechanistic details of LC8 binding have remained elusive, hampered in part by ITC data analyses employing simple models that treat bivalent binding as a single event with a single binding affinity. We build on existing Bayesian ITC approaches to quantify thermodynamic parameters for multi-site binding interactions impacted by significant uncertainty in protein concentration. Using a two-site binding model, we identify positive cooperativity with high confidence for LC8 binding to multiple client peptides. In contrast, application of an identical model to the two-site binding between the coiled-coil NudE dimer and the intermediate chain of dynein reveals little evidence of cooperativity. We propose that cooperativity in the LC8 system drives the formation of saturated induced-dimer structures, the functional units of most LC8 complexes. In addition to these system-specific findings, our work advances general ITC analysis in two ways. First, we describe a previously unrecognized mathematical ambiguity in concentrations in standard binding models and clarify how it impacts the precision with which binding parameters are determinable in cases of high uncertainty in analyte concentrations. Second, building on observations in the LC8 system, we develop a system-agnostic heat map of practical parameter identifiability calculated from synthetic data which demonstrates that the ability to determine microscopic binding parameters is strongly dependent on both the parameters themselves and experimental conditions. The work serves as a foundation for determination of multi-step binding interactions, and we outline best practices for Bayesian analysis of ITC experiments.
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Affiliation(s)
- Aidan B Estelle
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, United States of America
| | - August George
- Department of Biomedical Engineering, School of Medicine, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Elisar J Barbar
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, United States of America
| | - Daniel M Zuckerman
- Department of Biomedical Engineering, School of Medicine, Oregon Health and Science University, Portland, Oregon, United States of America
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2
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Glockzin K, Kostomiris D, Minnow YVT, Suthagar K, Clinch K, Gai S, Buckler JN, Schramm VL, Tyler PC, Meek TD, Katzfuss A. Kinetic Characterization and Inhibition of Trypanosoma cruzi Hypoxanthine–Guanine Phosphoribosyltransferases. Biochemistry 2022; 61:2088-2105. [PMID: 36193631 PMCID: PMC9536471 DOI: 10.1021/acs.biochem.2c00312] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
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Chagas disease, caused by the parasitic protozoan Trypanosoma cruzi, affects over 8 million people
worldwide. Current antiparasitic treatments for Chagas disease are
ineffective in treating advanced, chronic stages of the disease, and
are noted for their toxicity. Like most parasitic protozoa, T. cruzi is unable to synthesize purines de novo, and relies on the salvage of preformed purines
from the host. Hypoxanthine–guanine phosphoribosyltransferases
(HGPRTs) are enzymes that are critical for the salvage of preformed
purines, catalyzing the formation of inosine monophosphate (IMP) and
guanosine monophosphate (GMP) from the nucleobases hypoxanthine and
guanine, respectively. Due to the central role of HGPRTs in purine
salvage, these enzymes are promising targets for the development of
new treatment methods for Chagas disease. In this study, we characterized
two gene products in the T. cruzi CL
Brener strain that encodes enzymes with functionally identical HGPRT
activities in vitro: TcA (TcCLB.509693.70) and TcC
(TcCLB.506457.30). The TcC isozyme was kinetically characterized to
reveal mechanistic details on catalysis, including identification
of the rate-limiting step(s) of catalysis. Furthermore, we identified
and characterized inhibitors of T. cruzi HGPRTs originally developed as transition-state analogue inhibitors
(TSAIs) of Plasmodium falciparum hypoxanthine–guanine–xanthine
phosphoribosyltransferase (PfHGXPRT), where the most
potent compound bound to T. cruzi HGPRT
with low nanomolar affinity. Our results validated the repurposing
of TSAIs to serve as selective inhibitors for orthologous molecular
targets, where primary and secondary structures as well as putatively
common chemical mechanisms are conserved.
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Affiliation(s)
- Kayla Glockzin
- Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Boulevard, College Station, Texas 77843-2128, United States
| | - Demetrios Kostomiris
- Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Boulevard, College Station, Texas 77843-2128, United States
| | - Yacoba V. T. Minnow
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461-1602, United States
| | - Kajitha Suthagar
- Ferrier Research Institute, Victoria University of Wellington, Gracefield Research Centre, 69 Gracefield Road, Gracefield, Lower Hutt 5010, New Zealand
| | - Keith Clinch
- Ferrier Research Institute, Victoria University of Wellington, Gracefield Research Centre, 69 Gracefield Road, Gracefield, Lower Hutt 5010, New Zealand
| | - Sinan Gai
- Ferrier Research Institute, Victoria University of Wellington, Gracefield Research Centre, 69 Gracefield Road, Gracefield, Lower Hutt 5010, New Zealand
| | - Joshua N. Buckler
- Ferrier Research Institute, Victoria University of Wellington, Gracefield Research Centre, 69 Gracefield Road, Gracefield, Lower Hutt 5010, New Zealand
| | - Vern L. Schramm
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461-1602, United States
| | - Peter C. Tyler
- Ferrier Research Institute, Victoria University of Wellington, Gracefield Research Centre, 69 Gracefield Road, Gracefield, Lower Hutt 5010, New Zealand
| | - Thomas D. Meek
- Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Boulevard, College Station, Texas 77843-2128, United States
| | - Ardala Katzfuss
- Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Boulevard, College Station, Texas 77843-2128, United States
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Forces Driving a Magic Bullet to Its Target: Revisiting the Role of Thermodynamics in Drug Design, Development, and Optimization. Life (Basel) 2022; 12:life12091438. [PMID: 36143474 PMCID: PMC9504344 DOI: 10.3390/life12091438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 09/02/2022] [Accepted: 09/03/2022] [Indexed: 11/27/2022] Open
Abstract
Drug discovery strategies have advanced significantly towards prioritizing target selectivity to achieve the longstanding goal of identifying “magic bullets” amongst thousands of chemical molecules screened for therapeutic efficacy. A myriad of emerging and existing health threats, including the SARS-CoV-2 pandemic, alarming increase in bacterial resistance, and potentially fatal chronic ailments, such as cancer, cardiovascular disease, and neurodegeneration, have incentivized the discovery of novel therapeutics in treatment regimens. The design, development, and optimization of lead compounds represent an arduous and time-consuming process that necessitates the assessment of specific criteria and metrics derived via multidisciplinary approaches incorporating functional, structural, and energetic properties. The present review focuses on specific methodologies and technologies aimed at advancing drug development with particular emphasis on the role of thermodynamics in elucidating the underlying forces governing ligand–target interaction selectivity and specificity. In the pursuit of novel therapeutics, isothermal titration calorimetry (ITC) has been utilized extensively over the past two decades to bolster drug discovery efforts, yielding information-rich thermodynamic binding signatures. A wealth of studies recognizes the need for mining thermodynamic databases to critically examine and evaluate prospective drug candidates on the basis of available metrics. The ultimate power and utility of thermodynamics within drug discovery strategies reside in the characterization and comparison of intrinsic binding signatures that facilitate the elucidation of structural–energetic correlations which assist in lead compound identification and optimization to improve overall therapeutic efficacy.
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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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Wang H, Nie X, You W, Huang W, Chen G, Gao F, Xia L, Zhang L, Wang L, Shen AZ, Wu KL, Ding SG, You YZ. Tug-of-War between Covalent Binding and Electrostatic Interaction Effectively Killing E. coli without Detectable Resistance. ACS APPLIED MATERIALS & INTERFACES 2021; 13:56838-56849. [PMID: 34816709 DOI: 10.1021/acsami.1c15868] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Antimicrobial resistance in Gram-negative bacteria has become one of the leading causes of morbidity and mortality and a serious worldwide public health concern due to the fact that Gram-negative bacteria have an additional outer membrane protecting them from an unwanted compound invading. It is still very difficult for antimicrobials to reach intracellular targets and very challenging to treat Gram-negative bacteria with the current strategies. Here, we found that (o-(bromomethyl)phenyl)boronic acid was incorporated into poly((2-N,N-diethyl)aminoethyl acrylate) (PDEA), forming a copolymer (poly(o-Bn-DEA)) having both phenylboronic acid (B) and ((2-N,N-diethyl)amino) (DEA) units. Poly(o-Bn-DEA) exhibits very strong intramolecular B-N coordination, which could highly promote the covalent binding of phenylboronic acid with lipopolysaccharide (LPS) on the outer membrane of E. coli and lodge poly(o-Bn-DEA) on the LPS layer on the surface of E. coli. Meanwhile, the strong electrostatic interaction between poly(o-Bn-DEA) and the negatively charged lipid preferred tugging the poly(o-Bn-DEA) into the lipid bilayer of E. coli. The combating interactions between covalent binding and electrostatic interaction form a tug-of-war action, which could trigger the lysis of the outer membrane, thereby killing Gram-negative E. coli effectively without detectable resistance.
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Affiliation(s)
- Haili Wang
- The Department of Pharmacy, The First Affiliated Hospital of University of Science and Technology of China, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230001, China
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xuan Nie
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Wei You
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Weiqiang Huang
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Guang Chen
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Fan Gao
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Lei Xia
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Lei Zhang
- The Department of Pharmacy, The First Affiliated Hospital of University of Science and Technology of China, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230001, China
| | - Longhai Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ai-Zong Shen
- The Department of Pharmacy, The First Affiliated Hospital of University of Science and Technology of China, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230001, China
| | - Kai-Le Wu
- Department of Otolaryngology Head & Neck Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, China
| | - Sheng-Gang Ding
- Department of Pediatrics, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, China
| | - Ye-Zi You
- The Department of Pharmacy, The First Affiliated Hospital of University of Science and Technology of China, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230001, China
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China
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Sherry D, Worth R, Ismail ZS, Sayed Y. Cantilever-centric mechanism of cooperative non-active site mutations in HIV protease: Implications for flap dynamics. J Mol Graph Model 2021; 106:107931. [PMID: 34030114 DOI: 10.1016/j.jmgm.2021.107931] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/26/2021] [Accepted: 04/14/2021] [Indexed: 11/16/2022]
Abstract
The HIV-1 protease is an important drug target in antiretroviral therapy due to the crucial role it plays in viral maturation. A greater understanding of the dynamics of the protease as a result of drug-induced mutations has been successfully elucidated using computational models in the past. We performed induced-fit docking studies and molecular dynamics simulations on the wild-type South African HIV-1 subtype C protease and two non-active site mutation-containing protease variants; HP3 PR and HP4 PR. The HP3 PR contained the I13V, I62V, and V77I mutations while HP4 PR contained the same mutations with the addition of the L33F mutation. The simulations were initiated in a cubic cell universe containing explicit solvent, with the protease variants beginning in the fully closed conformation. The trajectory for each simulation totalled 50 ns. The results indicate that the mutations increase the dynamics of the flap, hinge, fulcrum and cantilever regions when compared to the wild-type protease while in complex with protease inhibitors. Specifically, these mutations result in the protease favouring the semi-open conformation when in complex with inhibitors. Moreover, the HP4 PR adopted curled flap tip conformers which coordinated several water molecules into the active site in a manner that may reduce inhibitor binding affinity. The mutations affected the thermodynamic landscape of inhibitor binding as there were fewer observable chemical contacts between the mutated variants and saquinavir, atazanavir and darunavir. These data help to elucidate the biophysical basis for the selection of cooperative non-active site mutations by the HI virus.
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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
| | - Roland Worth
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, 2050, South Africa
| | - Zaahida Sheik Ismail
- 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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Hüfner-Wulsdorf T, Klebe G. Advancing GIST-Based Solvent Functionals through Multiobjective Optimization of Solvent Enthalpy and Entropy Scoring Terms. J Chem Inf Model 2020; 60:6654-6665. [DOI: 10.1021/acs.jcim.0c01133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Tobias Hüfner-Wulsdorf
- Institut für Pharmazeutische Chemie, Philipps Universität Marburg, Marbacher Weg 6, 35037 Marburg, Germany
| | - Gerhard Klebe
- Institut für Pharmazeutische Chemie, Philipps Universität Marburg, Marbacher Weg 6, 35037 Marburg, Germany
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Zhang TH, Dai L, Barton JP, Du Y, Tan Y, Pang W, Chakraborty AK, Lloyd-Smith JO, Sun R. Predominance of positive epistasis among drug resistance-associated mutations in HIV-1 protease. PLoS Genet 2020; 16:e1009009. [PMID: 33085662 PMCID: PMC7605711 DOI: 10.1371/journal.pgen.1009009] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 11/02/2020] [Accepted: 07/24/2020] [Indexed: 12/12/2022] Open
Abstract
Drug-resistant mutations often have deleterious impacts on replication fitness, posing a fitness cost that can only be overcome by compensatory mutations. However, the role of fitness cost in the evolution of drug resistance has often been overlooked in clinical studies or in vitro selection experiments, as these observations only capture the outcome of drug selection. In this study, we systematically profile the fitness landscape of resistance-associated sites in HIV-1 protease using deep mutational scanning. We construct a mutant library covering combinations of mutations at 11 sites in HIV-1 protease, all of which are associated with resistance to protease inhibitors in clinic. Using deep sequencing, we quantify the fitness of thousands of HIV-1 protease mutants after multiple cycles of replication in human T cells. Although the majority of resistance-associated mutations have deleterious effects on viral replication, we find that epistasis among resistance-associated mutations is predominantly positive. Furthermore, our fitness data are consistent with genetic interactions inferred directly from HIV sequence data of patients. Fitness valleys formed by strong positive epistasis reduce the likelihood of reversal of drug resistance mutations. Overall, our results support the view that strong compensatory effects are involved in the emergence of clinically observed resistance mutations and provide insights to understanding fitness barriers in the evolution and reversion of drug resistance.
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Affiliation(s)
- Tian-hao Zhang
- Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
| | - Lei Dai
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - John P. Barton
- Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA
| | - Yushen Du
- School of Medicine, ZheJiang University, Hangzhou, 210000, China
- Molecular and Medical Pharmacology, University of California, Los Angeles, CA 90095, USA
| | - Yuxiang Tan
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Wenwen Pang
- Department of Public Health Laboratory Science, West China School of Public Health, Sichuan University, Chengdu 610041, China
| | - Arup K. Chakraborty
- Institute for Medical Engineering and Science, Departments of Chemical Engineering, Physics, & Chemistry, Massachusetts Institute of Technology, MA 21309, USA
- Ragon Institute of MGH, MIT, & Harvard, Cambridge, MA 21309, USA
| | - James O. Lloyd-Smith
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA
| | - Ren Sun
- Molecular and Medical Pharmacology, University of California, Los Angeles, CA 90095, USA
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Lee KE, Bharadwaj S, Yadava U, Kang SG. Computational and In Vitro Investigation of (-)-Epicatechin and Proanthocyanidin B2 as Inhibitors of Human Matrix Metalloproteinase 1. Biomolecules 2020; 10:biom10101379. [PMID: 32998374 PMCID: PMC7650666 DOI: 10.3390/biom10101379] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/17/2020] [Accepted: 09/24/2020] [Indexed: 01/16/2023] Open
Abstract
Matrix metalloproteinases 1 (MMP-1) energetically triggers the enzymatic proteolysis of extracellular matrix collagenase (ECM), resulting in progressive skin aging. Natural flavonoids are well known for their antioxidant properties and have been evaluated for inhibition of matrix metalloproteins in human. Recently, (-)-epicatechin and proanthocyanidin B2 were reported as essential flavanols from various natural reservoirs as potential anti-inflammatory and free radical scavengers. However, their molecular interactions and inhibitory potential against MMP-1 are not yet well studied. In this study, sequential absorption, distribution, metabolism, and excretion (ADME) profiling, quantum mechanics calculations, and molecular docking simulations by extra precision Glide protocol predicted the drug-likeness of (-)-epicatechin (−7.862 kcal/mol) and proanthocyanidin B2 (−8.145 kcal/mol) with the least reactivity and substantial binding affinity in the catalytic pocket of human MMP-1 by comparison to reference bioactive compound epigallocatechin gallate (−6.488 kcal/mol). These flavanols in docked complexes with MMP-1 were further studied by 500 ns molecular dynamics simulations that revealed substantial stability and intermolecular interactions, viz. hydrogen and ionic interactions, with essential residues, i.e., His218, Glu219, His222, and His228, in the active pocket of MMP-1. In addition, binding free energy calculations using the Molecular Mechanics Generalized Born Surface Area (MM/GBSA) method suggested the significant role of Coulomb interactions and van der Waals forces in the stability of respective docked MMP-1-flavonol complexes by comparison to MMP-1-epigallocatechin gallate; these observations were further supported by MMP-1 inhibition assay using zymography. Altogether with computational and MMP-1–zymography results, our findings support (-)-epicatechin as a comparatively strong inhibitor of human MMP-1 with considerable drug-likeness against proanthocyanidin B2 in reference to epigallocatechin gallate.
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Affiliation(s)
- Kyung Eun Lee
- Department of Biotechnology, Institute of Biotechnology, College of Life and Applied Sciences, Yeungnam University, 280 Daehak-Ro, Gyeongsan, Gyeongbuk 38541, Korea; (K.E.L.); (S.B.)
| | - Shiv Bharadwaj
- Department of Biotechnology, Institute of Biotechnology, College of Life and Applied Sciences, Yeungnam University, 280 Daehak-Ro, Gyeongsan, Gyeongbuk 38541, Korea; (K.E.L.); (S.B.)
| | - Umesh Yadava
- Department of Physics, Deen Dayal Upadhyay Gorakhpur University, Gorakhpur, Uttar Pradesh 273009, India;
| | - Sang Gu Kang
- Department of Biotechnology, Institute of Biotechnology, College of Life and Applied Sciences, Yeungnam University, 280 Daehak-Ro, Gyeongsan, Gyeongbuk 38541, Korea; (K.E.L.); (S.B.)
- Stemforce, 313 Institute of Industrial Technology, Yeungnam University, 280 Daehak-Ro, Gyeongsan, Gyeongbuk 38541, Korea
- Correspondence:
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Binding Thermodynamics to Intrinsically Disordered Protein Domains. Methods Mol Biol 2020. [PMID: 32696371 DOI: 10.1007/978-1-0716-0524-0_22] [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: 09/18/2023]
Abstract
Many proteins are intrinsically disordered or contain one or more disordered domains. These domains can participate in binding interactions with other proteins or small ligands. Binding to intrinsically disordered protein domains requires the folding or structuring of those regions such that they can establish well-defined stoichiometric interactions. Since, in such a situation binding is coupled to folding, the energetics of those two events is reflected in the measured binding thermodynamics. In this protocol, we illustrate the thermodynamic differences between binding coupled to folding and binding independent of folding for the same protein. As an example, we use the HIV-1 envelope glycoprotein gp120 that contains structured as well as disordered domains. In the experiments presented, the binding of gp120 to molecules that bind to disordered regions and trigger structuring (CD4 or MAb 17b) and to molecules that bind to structured regions and do not induce conformational structuring (MAb b12) is discussed.
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11
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Maseko S, Padayachee E, Maphumulo S, Govender T, Sayed Y, Maguire G, Lin J, Naicker T, Baijnath S, Gerhardus KH. Kinetic and thermodynamic characterisation of HIV-protease inhibitors against E35D↑G↑S mutant in the South African HIV-1 subtype C protease. J Enzyme Inhib Med Chem 2019; 34:1451-1456. [PMID: 31409143 PMCID: PMC6713120 DOI: 10.1080/14756366.2019.1636234] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Herein, we report the effect of nine FDA approved protease inhibitor drugs against a new HIV-1 subtype C mutant protease, E35D↑G↑S. The mutant has five mutations, E35D, two insertions, position 36 (G and S), and D60E. Kinetics, inhibition constants, vitality, Gibbs free binding energies are reported. The variant showed a decreased affinity for substrate and low catalytic efficiency compared to the wild type. There was a significant decrease in the binding of seven FDA approved protease inhibitors against the mutant (p < .0001). Amprenavir and ritonavir showed the least decrease, but still significant reduced activity in comparison to the wildtype (4 and 5 folds, respectively, p = .0021 and .003, respectively). Nelfinavir and atazanavir were the worst inhibitors against the variant as seen from the IC50, with values of 1401 ± 3.0 and 685 ± 3.0 nM, respectively. Thermodynamics data showed less favourable Gibbs free binding energies for the protease inhibitors to the mutant.
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Affiliation(s)
- Sibusiso Maseko
- a Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal , Durban , South Africa
| | - Eden Padayachee
- a Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal , Durban , South Africa
| | - Siyabonga Maphumulo
- a Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal , Durban , South Africa
| | - Thavendran Govender
- a Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal , Durban , South Africa
| | - Yasien Sayed
- b Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand , Wits , South Africa
| | - Glenn Maguire
- a Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal , Durban , South Africa.,c School of Chemistry and Physics, University of KwaZulu-Natal , Durban , South Africa
| | - Johnson Lin
- d School of Life Sciences, University of KwaZulu-Natal , Durban , South Africa
| | - Tricia Naicker
- a Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal , Durban , South Africa
| | - Sooraj Baijnath
- a Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal , Durban , South Africa
| | - Kruger Hendrik Gerhardus
- a Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal , Durban , South Africa
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12
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Nguyen TH, Rustenburg AS, Krimmer SG, Zhang H, Clark JD, Novick PA, Branson K, Pande VS, Chodera JD, Minh DDL. Bayesian analysis of isothermal titration calorimetry for binding thermodynamics. PLoS One 2018; 13:e0203224. [PMID: 30212471 PMCID: PMC6136728 DOI: 10.1371/journal.pone.0203224] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 08/16/2018] [Indexed: 12/04/2022] Open
Abstract
Isothermal titration calorimetry (ITC) is the only technique able to determine both the enthalpy and entropy of noncovalent association in a single experiment. The standard data analysis method based on nonlinear regression, however, provides unrealistically small uncertainty estimates due to its neglect of dominant sources of error. Here, we present a Bayesian framework for sampling from the posterior distribution of all thermodynamic parameters and other quantities of interest from one or more ITC experiments, allowing uncertainties and correlations to be quantitatively assessed. For a series of ITC measurements on metal:chelator and protein:ligand systems, the Bayesian approach yields uncertainties which represent the variability from experiment to experiment more accurately than the standard data analysis. In some datasets, the median enthalpy of binding is shifted by as much as 1.5 kcal/mol. A Python implementation suitable for analysis of data generated by MicroCal instruments (and adaptable to other calorimeters) is freely available online.
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Affiliation(s)
- Trung Hai Nguyen
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL, United States of America
| | - Ariën S. Rustenburg
- Computational and Systems Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, United States of America
- Graduate Program in Physiology, Biophysics, and Systems Biology, Weill Cornell Medical College, New York, NY, United States of America
| | - Stefan G. Krimmer
- Department of Pharmaceutical Chemistry, University of Marburg, Marbacher Weg 6, Marburg, Germany
| | - Hexi Zhang
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL, United States of America
| | - John D. Clark
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL, United States of America
| | - Paul A. Novick
- Department of Chemistry, Stanford University, Stanford, CA, United States of America
| | - Kim Branson
- Department of Chemistry, Stanford University, Stanford, CA, United States of America
| | - Vijay S. Pande
- Department of Chemistry, Stanford University, Stanford, CA, United States of America
| | - John D. Chodera
- Computational and Systems Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, United States of America
- * E-mail: (JDC); (DDLM)
| | - David D. L. Minh
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL, United States of America
- * E-mail: (JDC); (DDLM)
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13
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Zondagh J, Williams A, Achilonu I, Dirr HW, Sayed Y. Overexpression, Purification and Functional Characterisation of Wild-Type HIV-1 Subtype C Protease and Two Variants Using a Thioredoxin and His-Tag Protein Fusion System. Protein J 2018; 37:369-379. [PMID: 29869126 DOI: 10.1007/s10930-018-9779-5] [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] [Indexed: 11/27/2022]
Abstract
In recent years, various strategies have been used to overexpress and purify HIV-1 protease because it is an essential drug target in anti-retroviral therapy. Obtaining sufficient quantities of the enzyme, however, remains challenging. Overexpression of large quantities is prevented due to the enzyme's autolytic nature and its inherent cytotoxicity in Escherichia coli cells. Here, we describe a novel HIV-1 protease purification method using a thioredoxin-hexahistidine fusion system for the wild-type and two variant proteases. The fusion proteases were overexpressed in E. coli and recovered by immobilised metal ion affinity chromatography. The proteases were cleaved from the fusion constructs using thrombin. When compared to the standard overexpression and purification protocol in use in our laboratory, the expression of the fusion-derived wild-type protease was increased from 0.83 to 2.5 mg/l of culture medium. The expression levels of the two variant proteases ranged from 1.5 to 2 mg/l of culture medium. The fusion wild-type and variant proteases were inactive before the cleavage of the thioredoxin-hexahistidine fusion tag as no enzymatic activity was observed. The proteases were, however, active after cleavage of the tag. The novel thioredoxin-hexahistidine fusion system, therefore, enables the successful overexpression and purification of catalytically active HIV-1 proteases.
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Affiliation(s)
- Jake Zondagh
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of Witwatersrand, Johannesburg, 2050, South Africa
| | - Alison Williams
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of Witwatersrand, Johannesburg, 2050, South Africa
| | - Ikechukwu Achilonu
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of Witwatersrand, Johannesburg, 2050, South Africa
| | - Heini W Dirr
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of Witwatersrand, Johannesburg, 2050, 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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14
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Martinelli LKB, Rotta M, Villela AD, Rodrigues-Junior VS, Abbadi BL, Trindade RV, Petersen GO, Danesi GM, Nery LR, Pauli I, Campos MM, Bonan CD, de Souza ON, Basso LA, Santos DS. Functional, thermodynamics, structural and biological studies of in silico-identified inhibitors of Mycobacterium tuberculosis enoyl-ACP(CoA) reductase enzyme. Sci Rep 2017; 7:46696. [PMID: 28436453 PMCID: PMC5402281 DOI: 10.1038/srep46696] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 03/28/2017] [Indexed: 11/25/2022] Open
Abstract
Novel chemotherapeutics agents are needed to kill Mycobacterium tuberculosis, the main causative agent of tuberculosis (TB). The M. tuberculosis 2-trans-enoyl-ACP(CoA) reductase enzyme (MtInhA) is the druggable bona fide target of isoniazid. New chemotypes were previously identified by two in silico approaches as potential ligands to MtInhA. The inhibition mode was determined by steady-state kinetics for seven compounds that inhibited MtInhA activity. Dissociation constant values at different temperatures were determined by protein fluorescence spectroscopy. van't Hoff analyses of ligand binding to MtInhA:NADH provided the thermodynamic signatures of non-covalent interactions (ΔH°, ΔS°, ΔG°). Phenotypic screening showed that five compounds inhibited in vitro growth of M. tuberculosis H37Rv strain. Labio_16 and Labio_17 compounds also inhibited the in vitro growth of PE-003 multidrug-resistant strain. Cytotoxic effects on Hacat, Vero and RAW 264.7 cell lines were assessed for the latter two compounds. The Labio_16 was bacteriostatic and Labio_17 bactericidal in an M. tuberculosis-infected macrophage model. In Zebrafish model, Labio_16 showed no cardiotoxicity whereas Labio_17 showed dose-dependent cardiotoxicity. Accordingly, a model was built for the MtInhA:NADH:Labio_16 ternary complex. The results show that the Labio_16 compound is a direct inhibitor of MtInhA, and it may represent a hit for the development of chemotherapeutic agents to treat TB.
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Affiliation(s)
- Leonardo K. B. Martinelli
- Instituto Nacional de Ciência e Tecnologia em Tuberculose (INCT-TB), Centro de Pesquisas em Biologia Molecular e Funcional, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900, Porto Alegre, RS, Brazil
| | - Mariane Rotta
- Instituto Nacional de Ciência e Tecnologia em Tuberculose (INCT-TB), Centro de Pesquisas em Biologia Molecular e Funcional, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900, Porto Alegre, RS, Brazil
| | - Anne D. Villela
- Instituto Nacional de Ciência e Tecnologia em Tuberculose (INCT-TB), Centro de Pesquisas em Biologia Molecular e Funcional, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900, Porto Alegre, RS, Brazil
| | - Valnês S. Rodrigues-Junior
- Instituto Nacional de Ciência e Tecnologia em Tuberculose (INCT-TB), Centro de Pesquisas em Biologia Molecular e Funcional, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900, Porto Alegre, RS, Brazil
| | - Bruno L. Abbadi
- Instituto Nacional de Ciência e Tecnologia em Tuberculose (INCT-TB), Centro de Pesquisas em Biologia Molecular e Funcional, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900, Porto Alegre, RS, Brazil
| | - Rogério V. Trindade
- Instituto Nacional de Ciência e Tecnologia em Tuberculose (INCT-TB), Centro de Pesquisas em Biologia Molecular e Funcional, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900, Porto Alegre, RS, Brazil
| | - Guilherme O. Petersen
- Instituto Nacional de Ciência e Tecnologia em Tuberculose (INCT-TB), Centro de Pesquisas em Biologia Molecular e Funcional, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900, Porto Alegre, RS, Brazil
| | - Giuliano M. Danesi
- Instituto de Toxicologia e Farmacologia, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900, Porto Alegre, RS, Brazil
- Faculdade de Medicina, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900, Porto Alegre, RS, Brazil
| | - Laura R. Nery
- Laboratório de Neuroquímica e Psicofarmacologia, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900, Porto Alegre, RS, Brazil
| | - Ivani Pauli
- Laboratório de Bioinformática, Modelagem e Simulação de Biossistemas – LABIO, Faculdade de Informática, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900, Porto Alegre, RS, Brazil
| | - Maria M. Campos
- Instituto de Toxicologia e Farmacologia, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900, Porto Alegre, RS, Brazil
- Faculdade de Odontologia, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900, Porto Alegre, RS, Brazil
| | - Carla D. Bonan
- Laboratório de Neuroquímica e Psicofarmacologia, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900, Porto Alegre, RS, Brazil
| | - Osmar Norberto de Souza
- Laboratório de Bioinformática, Modelagem e Simulação de Biossistemas – LABIO, Faculdade de Informática, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900, Porto Alegre, RS, Brazil
- Laboratório de FarmInformática - FarmInf, Faculdade de Farmácia, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900, Porto Alegre, RS, Brazil
| | - Luiz A. Basso
- Instituto Nacional de Ciência e Tecnologia em Tuberculose (INCT-TB), Centro de Pesquisas em Biologia Molecular e Funcional, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900, Porto Alegre, RS, Brazil
| | - Diogenes S. Santos
- Instituto Nacional de Ciência e Tecnologia em Tuberculose (INCT-TB), Centro de Pesquisas em Biologia Molecular e Funcional, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900, Porto Alegre, RS, Brazil
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15
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Claveria-Gimeno R, Vega S, Abian O, Velazquez-Campoy A. A look at ligand binding thermodynamics in drug discovery. Expert Opin Drug Discov 2017; 12:363-377. [DOI: 10.1080/17460441.2017.1297418] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Rafael Claveria-Gimeno
- Institute of Biocomputation and Physics of Complex Systems (BIFI), IQFR-CSIC-BIFI and GBsC-CSIC-BIFI Joint Units, Universidad de Zaragoza, Zaragoza, Spain
- Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, Spain
- Aragon Institute for Health Research (IIS Aragon), Zaragoza, Spain
| | - Sonia Vega
- Institute of Biocomputation and Physics of Complex Systems (BIFI), IQFR-CSIC-BIFI and GBsC-CSIC-BIFI Joint Units, Universidad de Zaragoza, Zaragoza, Spain
| | - Olga Abian
- Institute of Biocomputation and Physics of Complex Systems (BIFI), IQFR-CSIC-BIFI and GBsC-CSIC-BIFI Joint Units, Universidad de Zaragoza, Zaragoza, Spain
- Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, Spain
- Aragon Institute for Health Research (IIS Aragon), Zaragoza, Spain
- Department of Biochemistry and Molecular and Cell Biology, Universidad de Zaragoza, Zaragoza, Spain
- Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), Barcelona, Spain
| | - Adrian Velazquez-Campoy
- Institute of Biocomputation and Physics of Complex Systems (BIFI), IQFR-CSIC-BIFI and GBsC-CSIC-BIFI Joint Units, Universidad de Zaragoza, Zaragoza, Spain
- Aragon Institute for Health Research (IIS Aragon), Zaragoza, Spain
- Department of Biochemistry and Molecular and Cell Biology, Universidad de Zaragoza, Zaragoza, Spain
- Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), Barcelona, Spain
- Fundación ARAID, Government of Aragon, Zaragoza, Spain
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16
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Schön A, Freire E. Enthalpy screen of drug candidates. Anal Biochem 2016; 513:1-6. [PMID: 27567994 DOI: 10.1016/j.ab.2016.08.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 08/09/2016] [Accepted: 08/23/2016] [Indexed: 12/11/2022]
Abstract
The enthalpic and entropic contributions to the binding affinity of drug candidates have been acknowledged to be important determinants of the quality of a drug molecule. These quantities, usually summarized in the thermodynamic signature, provide a rapid assessment of the forces that drive the binding of a ligand. Having access to the thermodynamic signature in the early stages of the drug discovery process will provide critical information towards the selection of the best drug candidates for development. In this paper, the Enthalpy Screen technique is presented. The enthalpy screen allows fast and accurate determination of the binding enthalpy for hundreds of ligands. As such, it appears to be ideally suited to aid in the ranking of the hundreds of hits that are usually identified after standard high throughput screening.
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Affiliation(s)
- Arne Schön
- Department of Biology, Johns Hopkins University, 3400 North Charles, Baltimore, MD 21218, USA
| | - Ernesto Freire
- Department of Biology, Johns Hopkins University, 3400 North Charles, Baltimore, MD 21218, USA.
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17
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Kurt Yilmaz N, Swanstrom R, Schiffer CA. Improving Viral Protease Inhibitors to Counter Drug Resistance. Trends Microbiol 2016; 24:547-557. [PMID: 27090931 DOI: 10.1016/j.tim.2016.03.010] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 03/18/2016] [Accepted: 03/30/2016] [Indexed: 12/13/2022]
Abstract
Drug resistance is a major problem in health care, undermining therapy outcomes and necessitating novel approaches to drug design. Extensive studies on resistance to viral protease inhibitors, particularly those of HIV-1 and hepatitis C virus (HCV) protease, revealed a plethora of information on the structural and molecular mechanisms underlying resistance. These insights led to several strategies to improve viral protease inhibitors to counter resistance, such as exploiting the essential biological function and leveraging evolutionary constraints. Incorporation of these strategies into structure-based drug design can minimize vulnerability to resistance, not only for viral proteases but for other quickly evolving drug targets as well, toward designing inhibitors one step ahead of evolution to counter resistance with more intelligent and rational design.
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Affiliation(s)
- Nese Kurt Yilmaz
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Ronald Swanstrom
- Department of Biochemistry and Biophysics, and the UNC Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Celia A Schiffer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA.
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18
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Soumana DI, Kurt Yilmaz N, Prachanronarong KL, Aydin C, Ali A, Schiffer CA. Structural and Thermodynamic Effects of Macrocyclization in HCV NS3/4A Inhibitor MK-5172. ACS Chem Biol 2016; 11:900-9. [PMID: 26682473 DOI: 10.1021/acschembio.5b00647] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Recent advances in direct-acting antivirals against Hepatitis C Virus (HCV) have led to the development of potent inhibitors, including MK-5172, that target the viral NS3/4A protease with relatively low susceptibility to resistance. MK-5172 has a P2-P4 macrocycle and a unique binding mode among current protease inhibitors where the P2 quinoxaline packs against the catalytic residues H57 and D81. However, the effect of macrocyclization on this binding mode is not clear, as is the relation between macrocyclization, thermodynamic stabilization, and susceptibility to the resistance mutation A156T. We have determined high-resolution crystal structures of linear and P1-P3 macrocyclic analogs of MK-5172 bound to WT and A156T protease and compared these structures, their molecular dynamics, and experimental binding thermodynamics to the parent compound. We find that the "unique" binding mode of MK-5172 is conserved even when the P2-P4 macrocycle is removed or replaced with a P1-P3 macrocycle. While beneficial to decreasing the entropic penalty associated with binding, the constraint exerted by the P2-P4 macrocycle prevents efficient rearrangement to accommodate the A156T mutation, a deficit alleviated in the linear and P1-P3 analogs. Design of macrocyclic inhibitors against NS3/4A needs to achieve the best balance between exerting optimal conformational constraint for enhancing potency, fitting within the substrate envelope and allowing adaptability to be robust against resistance mutations.
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Affiliation(s)
- Djadé I. Soumana
- Department of Biochemistry
and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, Massachusetts 01605, United States
| | - Nese Kurt Yilmaz
- Department of Biochemistry
and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, Massachusetts 01605, United States
| | - Kristina L. Prachanronarong
- Department of Biochemistry
and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, Massachusetts 01605, United States
| | - Cihan Aydin
- Department of Biochemistry
and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, Massachusetts 01605, United States
| | - Akbar Ali
- Department of Biochemistry
and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, Massachusetts 01605, United States
| | - Celia A. Schiffer
- Department of Biochemistry
and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, Massachusetts 01605, United States
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19
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20
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Effects of drug-resistant mutations on the dynamic properties of HIV-1 protease and inhibition by Amprenavir and Darunavir. Sci Rep 2015; 5:10517. [PMID: 26012849 PMCID: PMC4444956 DOI: 10.1038/srep10517] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/16/2015] [Indexed: 12/20/2022] Open
Abstract
Molecular dynamics simulations are performed to investigate the dynamic properties of wild-type HIV-1 protease and its two multi-drug-resistant variants (Flap + (L10I/G48V/I54V/V82A) and Act (V82T/I84V)) as well as their binding with APV and DRV inhibitors. The hydrophobic interactions between flap and 80 s (80’s) loop residues (mainly I50-I84’ and I50’-I84) play an important role in maintaining the closed conformation of HIV-1 protease. The double mutation in Act variant weakens the hydrophobic interactions, leading to the transition from closed to semi-open conformation of apo Act. APV or DRV binds with HIV-1 protease via both hydrophobic and hydrogen bonding interactions. The hydrophobic interactions from the inhibitor is aimed to the residues of I50 (I50’), I84 (I84’), and V82 (V82’) which create hydrophobic core clusters to further stabilize the closed conformation of flaps, and the hydrogen bonding interactions are mainly focused with the active site of HIV-1 protease. The combined change in the two kinds of protease-inhibitor interactions is correlated with the observed resistance mutations. The present study sheds light on the microscopic mechanism underlying the mutation effects on the dynamics of HIV-1 protease and the inhibition by APV and DRV, providing useful information to the design of more potent and effective HIV-1 protease inhibitors.
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21
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Zhao H, Piszczek G, Schuck P. SEDPHAT--a platform for global ITC analysis and global multi-method analysis of molecular interactions. Methods 2015; 76:137-148. [PMID: 25477226 PMCID: PMC4380758 DOI: 10.1016/j.ymeth.2014.11.012] [Citation(s) in RCA: 233] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 11/19/2014] [Accepted: 11/20/2014] [Indexed: 01/02/2023] Open
Abstract
Isothermal titration calorimetry experiments can provide significantly more detailed information about molecular interactions when combined in global analysis. For example, global analysis can improve the precision of binding affinity and enthalpy, and of possible linkage parameters, even for simple bimolecular interactions, and greatly facilitate the study of multi-site and multi-component systems with competition or cooperativity. A pre-requisite for global analysis is the departure from the traditional binding model, including an 'n'-value describing unphysical, non-integral numbers of sites. Instead, concentration correction factors can be introduced to account for either errors in the concentration determination or for the presence of inactive fractions of material. SEDPHAT is a computer program that embeds these ideas and provides a graphical user interface for the seamless combination of biophysical experiments to be globally modeled with a large number of different binding models. It offers statistical tools for the rigorous determination of parameter errors, correlations, as well as advanced statistical functions for global ITC (gITC) and global multi-method analysis (GMMA). SEDPHAT will also take full advantage of error bars of individual titration data points determined with the unbiased integration software NITPIC. The present communication reviews principles and strategies of global analysis for ITC and its extension to GMMA in SEDPHAT. We will also introduce a new graphical tool for aiding experimental design by surveying the concentration space and generating simulated data sets, which can be subsequently statistically examined for their information content. This procedure can replace the 'c'-value as an experimental design parameter, which ceases to be helpful for multi-site systems and in the context of gITC.
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Affiliation(s)
- Huaying Zhao
- Dynamics of Macromolecular Assembly Section, Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Grzegorz Piszczek
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Peter Schuck
- Dynamics of Macromolecular Assembly Section, Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA.
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22
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Is there a link between selectivity and binding thermodynamics profiles? Drug Discov Today 2015; 20:86-94. [DOI: 10.1016/j.drudis.2014.09.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 09/02/2014] [Accepted: 09/17/2014] [Indexed: 01/29/2023]
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23
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Velazquez-Campoy A, Leavitt SA, Freire E. Characterization of protein-protein interactions by isothermal titration calorimetry. Methods Mol Biol 2015; 1278:183-204. [PMID: 25859950 DOI: 10.1007/978-1-4939-2425-7_11] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The analysis of protein-protein interactions has attracted the attention of many researchers from both a fundamental point of view and a practical point of view. From a fundamental point of view, the development of an understanding of the signaling events triggered by the interaction of two or more proteins provides key information to elucidate the functioning of many cell processes. From a practical point of view, understanding protein-protein interactions at a quantitative level provides the foundation for the development of antagonists or agonists of those interactions. Isothermal Titration Calorimetry (ITC) is the only technique with the capability of measuring not only binding affinity but the enthalpic and entropic components that define affinity. Over the years, isothermal titration calorimeters have evolved in sensitivity and accuracy. Today, TA Instruments and MicroCal market instruments with the performance required to evaluate protein-protein interactions. In this methods paper, we describe general procedures to analyze heterodimeric (porcine pancreatic trypsin binding to soybean trypsin inhibitor) and homodimeric (bovine pancreatic α-chymotrypsin) protein associations by ITC.
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Affiliation(s)
- Adrian Velazquez-Campoy
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Unit IQFR-CSIC-BIFI, Universidad de Zaragoza, Zaragoza, Spain,
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24
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Nørholm AB, Francotte P, Goffin E, Botez I, Danober L, Lestage P, Pirotte B, Kastrup JS, Olsen L, Oostenbrink C. Thermodynamic characterization of new positive allosteric modulators binding to the glutamate receptor A2 ligand-binding domain: combining experimental and computational methods unravels differences in driving forces. J Chem Inf Model 2014; 54:3404-16. [PMID: 25420075 DOI: 10.1021/ci500559b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Positive allosteric modulation of the ionotropic glutamate receptor GluA2 presents a potential treatment of cognitive disorders, for example, Alzheimer's disease. In the present study, we describe the synthesis, pharmacology, and thermodynamic studies of a series of monofluoro-substituted 3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxides. Measurements of ligand binding by isothermal titration calorimetry (ITC) showed similar binding affinities for the modulator series at the GluA2 LBD but differences in the thermodynamic driving forces. Binding of 5c (7-F) and 6 (no-F) is enthalpy driven, and 5a (5-F) and 5b (6-F) are entropy driven. For 5d (8-F), both quantities were equal in size. Thermodynamic integration (TI) and one-step perturbation (OSP) were used to calculate the relative binding affinity of the modulators. The OSP calculations had a higher predictive power than those from TI, and combined with the shorter total simulation time, we found the OSP method to be more effective for this setup. Furthermore, from the molecular dynamics simulations, we extracted the enthalpies and entropies, and along with the ITC data, this suggested that the differences in binding free energies are largely explained by the direct ligand-surrounding enthalpies. Furthermore, we used the OSP setup to predict binding affinities for a series of polysubstituted fluorine compounds and monosubstituted methyl compounds and used these predictions to characterize the modulator binding pocket for this scaffold of positive allosteric modulators.
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Affiliation(s)
- Ann-Beth Nørholm
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, DK-2100 Copenhagen, Denmark
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25
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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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Vega S, Abian O, Velazquez-Campoy A. A unified framework based on the binding polynomial for characterizing biological systems by isothermal titration calorimetry. Methods 2014; 76:99-115. [PMID: 25305413 DOI: 10.1016/j.ymeth.2014.09.010] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/26/2014] [Accepted: 09/29/2014] [Indexed: 01/10/2023] Open
Abstract
Isothermal titration calorimetry (ITC) has become the gold-standard technique for studying binding processes due to its high precision and sensitivity, as well as its capability for the simultaneous determination of the association equilibrium constant, the binding enthalpy and the binding stoichiometry. The current widespread use of ITC for biological systems has been facilitated by technical advances and the availability of commercial calorimeters. However, the complexity of data analysis for non-standard models is one of the most significant drawbacks in ITC. Many models for studying macromolecular interactions can be found in the literature, but it looks like each biological system requires specific modeling and data analysis approaches. The aim of this article is to solve this lack of unity and provide a unified methodological framework for studying binding interactions by ITC that can be applied to any experimental system. The apparent complexity of this methodology, based on the binding polynomial, is overcome by its easy generalization to complex systems.
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Affiliation(s)
- Sonia Vega
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Unit IQFR-CSIC-BIFI, Universidad de Zaragoza, Zaragoza, Spain
| | - Olga Abian
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Unit IQFR-CSIC-BIFI, Universidad de Zaragoza, Zaragoza, Spain; Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, Spain; IIS Aragón, Zaragoza, Spain; Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), Spain.
| | - Adrian Velazquez-Campoy
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Unit IQFR-CSIC-BIFI, Universidad de Zaragoza, Zaragoza, Spain; Department of Biochemistry and Molecular and Cell Biology, University of Zaragoza, Zaragoza, Spain; Fundacion ARAID, Government of Aragon, Spain.
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Differential thermodynamic driving force of first- and second-generation antihistamines to determine their binding affinity for human H1 receptors. Biochem Pharmacol 2014; 91:231-41. [PMID: 25065879 DOI: 10.1016/j.bcp.2014.07.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 07/17/2014] [Accepted: 07/17/2014] [Indexed: 01/03/2023]
Abstract
Differential binding sites for first- and second-generation antihistamines were indicated on the basis of the crystal structure of human histamine H1 receptors. In this study, we evaluated differences between the thermodynamic driving forces of first- and second-generation antihistamines for human H1 receptors and their structural determinants. The binding enthalpy and entropy of 20 antihistamines were estimated with the van't Hoff equation using their dissociation constants obtained from their displacement curves against the binding of [(3)H]mepyramine to membrane preparations of Chinese hamster ovary cells expressing human H1 receptors at various temperatures from 4°C to 37°C. Structural determinants of antihistamines for their thermodynamic binding properties were assessed by quantitative structure-activity relationship (QSAR) analyses. We found that entropy-dependent binding was more evident in second- than first-generation antihistamines, resulting in enthalpy-entropy compensation between the binding forces of first- and second-generation antihistamines. QSAR analyses indicated that enthalpy-entropy compensation was determined by the sum of degrees, maximal electrostatic potentials, water-accessible surface area and hydrogen binding acceptor count of antihistamines to regulate their affinity for receptors. In conclusion, it was revealed that entropy-dependent hydrophobic interaction was more important in the binding of second-generation antihistamines, even though the hydrophilicity of second-generation antihistamines is generally increased. Furthermore, their structural determinants responsible for enthalpy-entropy compensation were explored by QSAR analyses. These findings may contribute to understanding the fundamental mechanisms of how the affinity of ligands for their receptors is regulated.
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HIV protease: Multiple fold inhibition by silver nanoparticles—Spectrofluorimetric, thermodynamic and kinetic analysis. J Taiwan Inst Chem Eng 2014. [DOI: 10.1016/j.jtice.2014.01.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Kožíšek M, Lepšík M, Grantz Šašková K, Brynda J, Konvalinka J, Řezáčová P. Thermodynamic and structural analysis of HIV protease resistance to darunavir - analysis of heavily mutated patient-derived HIV-1 proteases. FEBS J 2014; 281:1834-47. [DOI: 10.1111/febs.12743] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Milan Kožíšek
- Institute of Organic Chemistry and Biochemistry; Academy of Sciences of the Czech Republic; Gilead Sciences and IOCB Research Center; Prague Czech Republic
| | - Martin Lepšík
- Institute of Organic Chemistry and Biochemistry; Academy of Sciences of the Czech Republic; Gilead Sciences and IOCB Research Center; Prague Czech Republic
| | - Klára Grantz Šašková
- Institute of Organic Chemistry and Biochemistry; Academy of Sciences of the Czech Republic; Gilead Sciences and IOCB Research Center; Prague Czech Republic
- Department of Biochemistry; Faculty of Science; Charles University; Prague Czech Republic
| | - Jiří Brynda
- Institute of Organic Chemistry and Biochemistry; Academy of Sciences of the Czech Republic; Gilead Sciences and IOCB Research Center; Prague Czech Republic
- Institute of Molecular Genetics; Academy of Sciences of the Czech Republic; Prague Czech Republic
| | - Jan Konvalinka
- Institute of Organic Chemistry and Biochemistry; Academy of Sciences of the Czech Republic; Gilead Sciences and IOCB Research Center; Prague Czech Republic
- Department of Biochemistry; Faculty of Science; Charles University; Prague Czech Republic
| | - Pavlína Řezáčová
- Institute of Organic Chemistry and Biochemistry; Academy of Sciences of the Czech Republic; Gilead Sciences and IOCB Research Center; Prague Czech Republic
- Institute of Molecular Genetics; Academy of Sciences of the Czech Republic; Prague Czech Republic
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Naicker P, Achilonu I, Fanucchi S, Fernandes M, Ibrahim MA, Dirr HW, Soliman ME, Sayed Y. Structural insights into the South African HIV-1 subtype C protease: impact of hinge region dynamics and flap flexibility in drug resistance. J Biomol Struct Dyn 2013; 31:1370-80. [DOI: 10.1080/07391102.2012.736774] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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31
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Weber IT, Waltman MJ, Mustyakimov M, Blakeley MP, Keen DA, Ghosh AK, Langan P, Kovalevsky AY. Joint X-ray/neutron crystallographic study of HIV-1 protease with clinical inhibitor amprenavir: insights for drug design. J Med Chem 2013; 56:5631-5. [PMID: 23772563 DOI: 10.1021/jm400684f] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
HIV-1 protease is an important target for the development of antiviral inhibitors to treat AIDS. A room-temperature joint X-ray/neutron structure of the protease in complex with clinical drug amprenavir has been determined at 2.0 Å resolution. The structure provides direct determination of hydrogen atom positions in the enzyme active site. Analysis of the enzyme-drug interactions suggests that some hydrogen bonds may be weaker than deduced from the non-hydrogen interatomic distances. This information may be valuable for the design of improved protease inhibitors.
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Affiliation(s)
- Irene T Weber
- Departments of Chemistry and Biology, Georgia State University , Atlanta, Georgia, United States
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Foulkes-Murzycki JE, Rosi C, Kurt Yilmaz N, Shafer RW, Schiffer CA. Cooperative effects of drug-resistance mutations in the flap region of HIV-1 protease. ACS Chem Biol 2013; 8:513-8. [PMID: 23252515 DOI: 10.1021/cb3006193] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Understanding the interdependence of multiple mutations in conferring drug resistance is crucial to the development of novel and robust inhibitors. As HIV-1 protease continues to adapt and evade inhibitors while still maintaining the ability to specifically recognize and efficiently cleave its substrates, the problem of drug resistance has become more complicated. Under the selective pressure of therapy, correlated mutations accumulate throughout the enzyme to compromise inhibitor binding, but characterizing their energetic interdependency is not straightforward. A particular drug resistant variant (L10I/G48V/I54V/V82A) displays extreme entropy-enthalpy compensation relative to wild-type enzyme but a similar variant (L10I/G48V/I54A/V82A) does not. Individual mutations of sites in the flaps (residues 48 and 54) of the enzyme reveal that the thermodynamic effects are not additive. Rather, the thermodynamic profile of the variants is interdependent on the cooperative effects exerted by a particular combination of mutations simultaneously present.
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Affiliation(s)
- Jennifer E. Foulkes-Murzycki
- Department of Biochemistry and
Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, Massachusetts
01605, United States
| | - Christina Rosi
- Department of Biochemistry and
Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, Massachusetts
01605, United States
| | - Nese Kurt Yilmaz
- Department of Biochemistry and
Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, Massachusetts
01605, United States
| | - Robert W. Shafer
- Division
of Infectious Diseases,
Department of Medicine, Stanford University, Stanford, California 94305, United States
| | - Celia A. Schiffer
- Department of Biochemistry and
Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, Massachusetts
01605, United States
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Burnley BT, Afonine PV, Adams PD, Gros P. Modelling dynamics in protein crystal structures by ensemble refinement. eLife 2012; 1:e00311. [PMID: 23251785 PMCID: PMC3524795 DOI: 10.7554/elife.00311] [Citation(s) in RCA: 207] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 10/23/2012] [Indexed: 11/13/2022] Open
Abstract
Single-structure models derived from X-ray data do not adequately account for the inherent, functionally important dynamics of protein molecules. We generated ensembles of structures by time-averaged refinement, where local molecular vibrations were sampled by molecular-dynamics (MD) simulation whilst global disorder was partitioned into an underlying overall translation–libration–screw (TLS) model. Modeling of 20 protein datasets at 1.1–3.1 Å resolution reduced cross-validated Rfree values by 0.3–4.9%, indicating that ensemble models fit the X-ray data better than single structures. The ensembles revealed that, while most proteins display a well-ordered core, some proteins exhibit a ‘molten core’ likely supporting functionally important dynamics in ligand binding, enzyme activity and protomer assembly. Order–disorder changes in HIV protease indicate a mechanism of entropy compensation for ordering the catalytic residues upon ligand binding by disordering specific core residues. Thus, ensemble refinement extracts dynamical details from the X-ray data that allow a more comprehensive understanding of structure–dynamics–function relationships. DOI:http://dx.doi.org/10.7554/eLife.00311.001 It has been clear since the early days of structural biology in the late 1950s that proteins and other biomolecules are continually changing shape, and that these changes have an important influence on both the structure and function of the molecules. X-ray diffraction can provide detailed information about the structure of a protein, but only limited information about how its structure fluctuates over time. Detailed information about the dynamic behaviour of proteins is essential for a proper understanding of a variety of processes, including catalysis, ligand binding and protein–protein interactions, and could also prove useful in drug design. Currently most of the X-ray crystal structures in the Protein Data Bank are ‘snap-shots’ with limited or no information about protein dynamics. However, X-ray diffraction patterns are affected by the dynamics of the protein, and also by distortions of the crystal lattice, so three-dimensional (3D) models of proteins ought to take these phenomena into account. Molecular-dynamics (MD) computer simulations transform 3D structures into 4D ‘molecular movies’ by predicting the movement of individual atoms. Combining MD simulations with crystallographic data has the potential to produce more realistic ensemble models of proteins in which the atomic fluctuations are represented by multiple structures within the ensemble. Moreover, in addition to improved structural information, this process—which is called ensemble refinement—can provide dynamical information about the protein. Earlier attempts to do this ran into problems because the number of model parameters needed was greater than the number of observed data points. Burnley et al. now overcome this problem by modelling local molecular vibrations with MD simulations and, at the same time, using a course-grain model to describe global disorder of longer length scales. Ensemble refinement of high-resolution X-ray diffraction datasets for 20 different proteins from the Protein Data Bank produced a better fit to the data than single structures for all 20 proteins. Ensemble refinement also revealed that 3 of the 20 proteins had a ‘molten core’, rather than the well-ordered residues core found in most proteins: this is likely to be important in various biological functions including ligand binding, filament formation and enzymatic function. Burnley et al. also showed that a HIV enzyme underwent an order–disorder transition that is likely to influence how this enzyme works, and that similar transitions might influence the interactions between the small-molecule drug Imatinib (also known as Gleevec) and the enzymes it targets. Ensemble refinement could be applied to the majority of crystallography data currently being collected, or collected in the past, so further insights into the properties and interactions of a variety of proteins and other biomolecules can be expected. DOI:http://dx.doi.org/10.7554/eLife.00311.002
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Affiliation(s)
- B Tom Burnley
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science , Utrecht University , Utrecht , The Netherlands
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Biophysical and computational fragment-based approaches to targeting protein-protein interactions: applications in structure-guided drug discovery. Q Rev Biophys 2012; 45:383-426. [PMID: 22971516 DOI: 10.1017/s0033583512000108] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Drug discovery has classically targeted the active sites of enzymes or ligand-binding sites of receptors and ion channels. In an attempt to improve selectivity of drug candidates, modulation of protein-protein interfaces (PPIs) of multiprotein complexes that mediate conformation or colocation of components of cell-regulatory pathways has become a focus of interest. However, PPIs in multiprotein systems continue to pose significant challenges, as they are generally large, flat and poor in distinguishing features, making the design of small molecule antagonists a difficult task. Nevertheless, encouragement has come from the recognition that a few amino acids - so-called hotspots - may contribute the majority of interaction-free energy. The challenges posed by protein-protein interactions have led to a wellspring of creative approaches, including proteomimetics, stapled α-helical peptides and a plethora of antibody inspired molecular designs. Here, we review a more generic approach: fragment-based drug discovery. Fragments allow novel areas of chemical space to be explored more efficiently, but the initial hits have low affinity. This means that they will not normally disrupt PPIs, unless they are tethered, an approach that has been pioneered by Wells and co-workers. An alternative fragment-based approach is to stabilise the uncomplexed components of the multiprotein system in solution and employ conventional fragment-based screening. Here, we describe the current knowledge of the structures and properties of protein-protein interactions and the small molecules that can modulate them. We then describe the use of sensitive biophysical methods - nuclear magnetic resonance, X-ray crystallography, surface plasmon resonance, differential scanning fluorimetry or isothermal calorimetry - to screen and validate fragment binding. Fragment hits can subsequently be evolved into larger molecules with higher affinity and potency. These may provide new leads for drug candidates that target protein-protein interactions and have therapeutic value.
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Ershov PV, Gnedenko OV, Mol'nar AA, Lisitsa AV, Ivanov AS, Archakov AI. [Thermodynamic analysis of dimerization inhibitors binding to HIV protease monomers]. BIOMEDIT︠S︡INSKAI︠A︡ KHIMII︠A︡ 2012; 58:43-9. [PMID: 22642151 DOI: 10.18097/pbmc20125801043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Here, we describe the analysis of kinetic and thermodynamic parameters for binding of peptide and nonpeptide dimerization inhibitors to immobilized HIV protease (HIVp) monomers by using surface plasmon resonance. Molecular interactions were investigated at different inhibitors concentrations (0-80 microM) and temperatures (15-35 degrees C). The kinetic, equilibrium and thermodynamic parameters have been determined. It was found that both inhibitors were characterized by similar interaction parameters. The complex formation is entropically driven process for both inhibitors. The entropic term(-TdeltaS) had the value about -20 kcal/mol while the enthalpic term (deltaH) had the positive value about 14 kcal/mol and counteracted the complex formation.
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Heal JW, Jimenez-Roldan JE, Wells SA, Freedman RB, Römer RA. Inhibition of HIV-1 protease: the rigidity perspective. ACTA ACUST UNITED AC 2012; 28:350-7. [PMID: 22291339 DOI: 10.1093/bioinformatics/btr683] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
MOTIVATION HIV-1 protease is a key drug target due to its role in the life cycle of the HIV-1 virus. Rigidity analysis using the software First is a computationally inexpensive method for inferring functional information from protein crystal structures. We evaluate the rigidity of 206 high-resolution (2 Å or better) X-ray crystal structures of HIV-1 protease and compare the effects of different inhibitors binding to the enzyme. RESULTS Inhibitor binding has little effect on the overall rigidity of the protein homodimer, including the rigidity of the active site. The principal effect of inhibitor binding on rigidity is to constrain the flexibility of the β-hairpin flaps, which move to allow access to the active site of the enzyme. We show that commercially available antiviral drugs which target HIV-1 protease can be divided into two classes, those which significantly affect flap rigidity and those which do not. The non-peptidic inhibitor tipranavir is distinctive in its consistently strong effect on flap rigidity. CONTACT jack.heal@warwick.ac.uk; r.roemer@warwick.ac.uk SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- J W Heal
- MOAC Doctoral Training Centre, University of Warwick, Coventry CV4 7AL, UK.
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37
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Bisubstrate adenylation inhibitors of biotin protein ligase from Mycobacterium tuberculosis. ACTA ACUST UNITED AC 2012; 18:1432-41. [PMID: 22118677 DOI: 10.1016/j.chembiol.2011.08.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 08/05/2011] [Accepted: 08/24/2011] [Indexed: 10/15/2022]
Abstract
The mycobacterial biotin protein ligase (MtBPL) globally regulates lipid metabolism in Mtb through the posttranslational biotinylation of acyl coenzyme A carboxylases involved in lipid biosynthesis that catalyze the first step in fatty acid biosynthesis and pyruvate coenzyme A carboxylase, a gluconeogenic enzyme vital for lipid catabolism. Here we describe the design, development, and evaluation of a rationally designed bisubstrate inhibitor of MtBPL. This inhibitor displays potent subnanomolar enzyme inhibition and antitubercular activity against multidrug resistant and extensively drug resistant Mtb strains. We show that the inhibitor decreases in vivo protein biotinylation of key enzymes involved in fatty acid biosynthesis and that the antibacterial activity is MtBPL dependent. Additionally, the gene encoding BPL was found to be essential in M. smegmatis. Finally, the X-ray cocrystal structure of inhibitor bound MtBPL was solved providing detailed insight for further structure-activity analysis. Collectively, these data suggest that MtBPL is a promising target for further antitubercular therapeutic development.
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Ershov PV, Gnedenko OV, Molnar AA, Lisitsa AV, Ivanov AS, Archakov AI. Kinetic and thermodynamic analysis of dimerization inhibitors binding to HIV protease monomers by surface plasmon resonance. BIOCHEMISTRY MOSCOW-SUPPLEMENT SERIES B-BIOMEDICAL CHEMISTRY 2012. [DOI: 10.1134/s1990750812010039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Aweda TA, Meares CF. Combination of isothermal titration calorimetry and time-resolved luminescence for high affinity antibody-ligand interaction thermodynamics and kinetics. Methods 2012; 56:145-53. [PMID: 21964396 PMCID: PMC3294027 DOI: 10.1016/j.ymeth.2011.09.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 09/09/2011] [Accepted: 09/14/2011] [Indexed: 11/30/2022] Open
Abstract
For experiments using synthetic ligands as probes for biological experiments, it is useful to determine the specificity and affinity of the ligands for their receptors. As ligands with higher affinities are developed (K(A)>10(8)M(-1); K(D)<10(-8)M), a new challenge arises: to measure these values accurately. Isothermal titration calorimetry measures heat produced or consumed during ligand binding, and also provides the equilibrium binding constant. However, as normally practiced, its range is limited. Displacement titration, where a competing weaker ligand is used to lower the apparent affinity of the stronger ligand, can be used to determine the binding affinity as well as the complete thermodynamic data for ligand-antibody complexes with very high affinity. These equilibrium data have been combined with kinetic measurements to yield the rate constants as well. We describe this methodology, using as an example antibody 2D12.5, which captures yttrium S-2-(4-aminobenzyl)-1, 4, 7, 10-tetraazacyclododecanetetraacetate.
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Affiliation(s)
- Tolulope A. Aweda
- Chemistry Department, University of California, Davis, CA 95616, USA
| | - Claude F. Meares
- Chemistry Department, University of California, Davis, CA 95616, USA
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40
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Wynn RM, Li J, Brautigam CA, Chuang JL, Chuang DT. Structural and biochemical characterization of human mitochondrial branched-chain α-ketoacid dehydrogenase phosphatase. J Biol Chem 2012; 287:9178-92. [PMID: 22291014 DOI: 10.1074/jbc.m111.314963] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The branched-chain α-ketoacid dehydrogenase phosphatase (BDP) component of the human branched-chain α-ketoacid dehydrogenase complex (BCKDC) has been expressed in Escherichia coli and purified in the soluble form. The monomeric BDP shows a strict dependence on Mn(2+) ions for phosphatase activity, whereas Mg(2+) and Ca(2+) ions do not support catalysis. Metal binding constants for BDP, determined by competition isothermal titration calorimetry, are 2.4 nm and 10 μm for Mn(2+) and Mg(2+) ions, respectively. Using the phosphorylated decarboxylase component (p-E1b) of BCKDC as a substrate, BDP shows a specific activity of 68 nmol/min/mg. The Ca(2+)-independent binding of BDP to the 24-meric transacylase (dihydrolipoyl transacylase; E2b) core of BCKDC results in a 3-fold increase in the dephosphorylation rate of p-E1b. However, the lipoyl prosthetic group on E2b is not essential for BDP binding or E2b-stimulated phosphatase activity. Acidic residues in the C-terminal linker of the E2b lipoyl domain are essential for the interaction between BDP and E2b. The BDP structure was determined by x-ray crystallography to 2.4 Å resolution. The BDP structure is dominated by a central β-sandwich. There are two protrusions forming a narrow cleft ∼10 Å wide, which constitutes the active site. The carboxylate moieties of acidic residues Asp-109, Asp-207, Asp-298, and Asp-337 in the active-site cleft participate in binding two metal ions. Substitutions of these residues with alanine nullify BDP phosphatase activity. Alteration of the nearby Arg-104 increases the K(m) for p-E1b peptide by 60-fold, suggesting that this residue is critical for the recognition of the native p-E1b protein.
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Affiliation(s)
- R Max Wynn
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9038, USA.
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Narang AS, Yamniuk AP, Zhang L, Comezoglu SN, Bindra DS, Varia S, Doyle ML, Badawy S. Reversible and pH-dependent weak drug-excipient binding does not affect oral bioavailability of high dose drugs. J Pharm Pharmacol 2012; 64:553-65. [DOI: 10.1111/j.2042-7158.2011.01435.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Abstract
Objectives
Drug-excipient binding can affect in-vitro drug release. Literature suggests that drug-excipient ionic binding interaction that is not disrupted by physiological salt concentration in the dissolution medium can impact a drug's oral bioavailability. We investigated whether nondisruption of interaction by physiological salt concentration was an adequate predictor of its biorelevance using the binding of a model amine high dose drug brivanib alaninate (BA) to croscarmellose sodium (CCS) as an example.
Methods
BA was formulated into an immediate release tablet using CCS as disintegrant by a wet granulation process. In-vitro drug release was carried out as a function of pH and buffer concentration of the medium. BA-CCS binding was studied in buffer solution and data fitted to a Langmuir isotherm. A simulation model and an isothermal titration calorimetry method were developed to assess the bioavailability risk and strength of drug-excipient binding interaction, independent of physiological salt concentration consideration.
Key findings
BA-CCS binding was pH-dependent, reversible, ionic, and not disrupted by increasing the buffer concentration in the dissolution medium. Absorption simulation predictions of no effect of CCS binding on BA's bioavailability were confirmed by a monkey pharmacokinetic study.
Conclusions
A pH-dependent and reversible weak drug-excipient binding interaction is unlikely to affect the oral bioavailability of high dose drugs.
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Affiliation(s)
- Ajit S Narang
- Drug Product Science and Technology, Bristol-Myers Squibb, Co., New Brunswick, USA
| | - Aaron P Yamniuk
- Protein Science and Structure, Bristol-Myers Squibb, Co., Princeton, NJ, USA
| | - Limin Zhang
- Analytical and Bioanalytical Development, Bristol-Myers Squibb, Co., New Brunswick, USA
| | - S Nilgun Comezoglu
- Biotransformation Department, Bristol-Myers Squibb, Co., Princeton, NJ, USA
| | - Dilbir S Bindra
- Drug Product Science and Technology, Bristol-Myers Squibb, Co., New Brunswick, USA
| | - Sailesh Varia
- Drug Product Science and Technology, Bristol-Myers Squibb, Co., New Brunswick, USA
| | - Michael L Doyle
- Protein Science and Structure, Bristol-Myers Squibb, Co., Princeton, NJ, USA
| | - Sherif Badawy
- Drug Product Science and Technology, Bristol-Myers Squibb, Co., New Brunswick, USA
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42
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Target–drug interactions: first principles and their application to drug discovery. Drug Discov Today 2012; 17:10-22. [DOI: 10.1016/j.drudis.2011.06.013] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 06/07/2011] [Accepted: 06/28/2011] [Indexed: 02/06/2023]
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Alvarenga ML, Kikhney J, Hannewald J, Metzger AU, Steffens KJ, Bomke J, Krah A, Wegener A. In-depth biophysical analysis of interactions between therapeutic antibodies and the extracellular domain of the epidermal growth factor receptor. Anal Biochem 2011; 421:138-51. [PMID: 22085444 DOI: 10.1016/j.ab.2011.10.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 10/21/2011] [Accepted: 10/22/2011] [Indexed: 12/12/2022]
Abstract
Targeting of the epidermal growth factor receptor (EGFR) with monoclonal antibodies has become an established antitumor strategy in clinical use or in late stages of drug development. The mAbs effector mechanisms have been widely analyzed based on in vivo or cell studies. Hereby we intend to complement these functional studies by investigating the mAb-EGFR interactions on a molecular level. Surface plasmon resonance, isothermal titration calorimetry, and static light scattering were employed to characterize the interactions of matuzumab, cetuximab, and panitumumab with the extracellular soluble form ecEGFR. The kinetic and thermodynamic determinants dissected the differences in mAbs binding mechanism toward ecEGFR. The quantitative stoichiometric data clearly demonstrated the bivalent binding of the mAbs to two ecEGFR molecules. Our results complement earlier studies on simultaneous binding of cetuximab and matuzumab. The antibodies retain their bivalent binding mode achieving a 1:2:1 complex formation. Interestingly the binding parameters remain nearly constant for the individual antibodies in this ternary assembly. In contrast the binding of panitumumab is almost exclusive either by directly blocking the accessibility for the second antibody or by negative allosteric modulation. Overall we provide a comprehensive biophysical dataset on binding parameters, the complex assembly, and relative epitope accessibility for therapeutic anti-EGFR antibodies.
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44
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Deng NJ, Zheng W, Gallicchio E, Levy RM. Insights into the dynamics of HIV-1 protease: a kinetic network model constructed from atomistic simulations. J Am Chem Soc 2011; 133:9387-94. [PMID: 21561098 DOI: 10.1021/ja2008032] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The conformational dynamics in the flaps of HIV-1 protease plays a crucial role in the mechanism of substrate binding. We develop a kinetic network model, constructed from detailed atomistic simulations, to determine the kinetic mechanisms of the conformational transitions in HIV-1 PR. To overcome the time scale limitation of conventional molecular dynamics (MD) simulations, our method combines replica exchange MD with transition path theory (TPT) to study the diversity and temperature dependence of the pathways connecting functionally important states of the protease. At low temperatures the large-scale flap opening is dominated by a small number of paths; at elevated temperatures the transition occurs through many structurally heterogeneous routes. The expanded conformation in the crystal structure 1TW7 is found to closely mimic a key intermediate in the flap-opening pathways at low temperature. We investigated the different transition mechanisms between the semi-open and closed forms. The calculated relaxation times reveal fast semi-open ↔ closed transitions, and infrequently the flaps fully open. The ligand binding rate predicted from this kinetic model increases by 38-fold from 285 to 309 K, which is in general agreement with experiments. To our knowledge, this is the first application of a network model constructed from atomistic simulations together with TPT to analyze conformational changes between different functional states of a natively folded protein.
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Affiliation(s)
- Nan-jie Deng
- BioMaPS Institute for Quantitative Biology and Department of Chemistry and Chemical Biology, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854, USA
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45
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Abstract
Almost any process in life is accompanied by heat changes which can be monitored by isothermal titration calorimetry (ITC) and differential scanning calorimetry (DSC). Both techniques are now established tools in fundamental research but over the last decade a clear tendency towards more problem-driven applications is noted. This review aims at summarizing these problem-oriented applications of microcalorimetry and the solutions both techniques can provide to problems in biotechnology. The biotechnological issues to which microcalorimetry has been successfully applied are as diverse as rational drug design, overcoming drug resistance, optimization of long-term stability of proteins, estimation of the bioavailability of drugs, control of complex pharmaceutical products or the optimization of gene delivery efficiency. The main limitation of microcalorimetry, which is the relatively large amounts of sample necessary for analysis, is less important in the biotechnology sector which frequently uses large-scale produced bulk products for analysis. The recently developed high-throughput DSC and ITC microcalorimeters will additionally reduce the labour intensity of these techniques. Due to the precision of microcalorimetric analyses and the versatility of processes which can be studied, it is expected that ITC and DSC will soon be key technologies in biotechnological research.
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Affiliation(s)
- Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/Prof. Albareda 1, 18008 Granada, Spain.
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46
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In vitro characterization of GS-8374, a novel phosphonate-containing inhibitor of HIV-1 protease with a favorable resistance profile. Antimicrob Agents Chemother 2011; 55:1366-76. [PMID: 21245449 DOI: 10.1128/aac.01183-10] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
GS-8374 is a novel bis-tetrahydrofuran HIV-1 protease (PR) inhibitor (PI) with a unique diethylphosphonate moiety. It was selected from a series of analogs containing various di(alkyl)phosphonate substitutions connected via a linker to the para position of a P-1 phenyl ring. GS-8374 inhibits HIV-1 PR with high potency (K(i) = 8.1 pM) and with no known effect on host proteases. Kinetic and thermodynamic analysis of GS-8374 binding to PR demonstrated an extremely slow off rate for the inhibitor and favorable contributions of both the enthalpic and entropic components to the total free binding energy. GS-8374 showed potent antiretroviral activity in T-cell lines, primary CD4(+) T cells (50% effective concentration [EC(50)] = 3.4 to 11.5 nM), and macrophages (EC(50) = 25.5 nM) and exhibited low cytotoxicity in multiple human cell types. The antiviral potency of GS-8374 was only moderately affected by human serum protein binding, and its combination with multiple approved antiretrovirals showed synergistic effects. When it was tested in a PhenoSense assay against a panel of 24 patient-derived viruses with high-level PI resistance, GS-8374 showed lower mean EC(50)s and lower fold resistance than any of the clinically approved PIs. Similar to other PIs, in vitro hepatic microsomal metabolism of GS-8374 was efficiently blocked by ritonavir, suggesting a potential for effective pharmacokinetic boosting in vivo. In summary, results from this broad in vitro pharmacological profiling indicate that GS-8374 is a promising candidate to be further assessed as a new antiretroviral agent with potential for clinical efficacy in both treatment-naïve and -experienced patients.
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47
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Abstract
The human immunodeficiency virus type 1 (HIV-1) protein Vif recruits the host E3 ubiquitin ligase, composed of cullin 5 (Cul5), Rbx2, Elongin B, and Elongin C (EloBC), to polyubiquitinate the antiviral protein APOBEC3G. Multiple regions in the C-terminal half of Vif interact with the E3 ligase. We have purified individual regions of Vif and investigated their thermodynamic contributions to the ligase assembly in vitro using isothermal titration calorimetry and fluorescence anisotropy. Our results quantify the high-affinity interactions between the Vif BC box and EloBC and between the Vif zinc finger and Cul5, as well as the modest interaction between the Vif cullin box and Cul5. Our purified Vif constructs also provide direct biochemical evidence that the Vif cullin box, containing the PPLP region, leads to the dimerization of Vif-EloBC complexes but not Cul5-Vif-EloBC complexes.
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48
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Garrec J, Cascella M, Rothlisberger U, Fleurat-Lessard P. Low Inhibiting Power of N···CO Based Peptidomimetic Compounds against HIV-1 Protease: Insights from a QM/MM Study. J Chem Theory Comput 2010. [DOI: 10.1021/ct9004728] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Julian Garrec
- Université de Lyon, École Normale Supérieure de Lyon, Laboratoire de Chimie − UMR 5182, 46 allée d’Italie, 69364 Lyon Cedex 07, France, Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland, and Laboratory of Computational Chemistry and Biochemistry, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Michele Cascella
- Université de Lyon, École Normale Supérieure de Lyon, Laboratoire de Chimie − UMR 5182, 46 allée d’Italie, 69364 Lyon Cedex 07, France, Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland, and Laboratory of Computational Chemistry and Biochemistry, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Ursula Rothlisberger
- Université de Lyon, École Normale Supérieure de Lyon, Laboratoire de Chimie − UMR 5182, 46 allée d’Italie, 69364 Lyon Cedex 07, France, Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland, and Laboratory of Computational Chemistry and Biochemistry, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Paul Fleurat-Lessard
- Université de Lyon, École Normale Supérieure de Lyon, Laboratoire de Chimie − UMR 5182, 46 allée d’Italie, 69364 Lyon Cedex 07, France, Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland, and Laboratory of Computational Chemistry and Biochemistry, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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49
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Cai Y, Schiffer CA. Decomposing the energetic impact of drug resistant mutations in HIV-1 protease on binding DRV. J Chem Theory Comput 2010; 6:1358-1368. [PMID: 20543885 DOI: 10.1021/ct9004678] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Darunavir (DRV) is a high affinity (4.5×10(-12) M, ΔG = -15.2 kcal/mol) HIV-1 protease inhibitor. Two drug-resistant protease variants FLAP+ (L10I, G48V, I54V, V82A) and ACT (V82T, I84V) decrease the binding affinity with DRV by 1.0 kcal/mol and 1.6 kcal/mol respectively. In this study the absolute and relative binding free energies of DRV with wild-type protease, FLAP+ and ACT were calculated with MM-PB/GBSA and thermodynamic integration methods, respectively. Free energy decomposition elucidated that the mutations conferred resistance by distorting the active site of HIV-1 protease so that the residues that lost binding free energy were not limited to the sites of mutation. Specifically the bis-tetrahydrofuranylurethane moiety of DRV maintained interactions with the FLAP+ and ACT variants, whereas the 4 - amino phenyl group lost more binding free energy with the protease in the FLAP+ and ACT complexes than in the wild-type protease which could account for the majority of the loss in binding free energy. This suggested that replacement of the 4 - amino phenyl group might generate new inhibitors less susceptible to the drug resistant mutations.
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Affiliation(s)
- Yufeng Cai
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605
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50
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Kawasaki Y, Chufan EE, Lafont V, Hidaka K, Kiso Y, Amzel LM, Freire E. How much binding affinity can be gained by filling a cavity? Chem Biol Drug Des 2010; 75:143-51. [PMID: 20028396 PMCID: PMC3209665 DOI: 10.1111/j.1747-0285.2009.00921.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Binding affinity optimization is critical during drug development. Here, we evaluate the thermodynamic consequences of filling a binding cavity with functionalities of increasing van der Waals radii (-H, -F, -Cl, and CH(3)) that improve the geometric fit without participating in hydrogen bonding or other specific interactions. We observe a binding affinity increase of two orders of magnitude. There appears to be three phases in the process. The first phase is associated with the formation of stable van der Waals interactions. This phase is characterized by a gain in binding enthalpy and a loss in binding entropy, attributed to a loss of conformational degrees of freedom. For the specific case presented in this article, the enthalpy gain amounts to -1.5 kcal/mol while the entropic losses amount to +0.9 kcal/mol resulting in a net 3.5-fold affinity gain. The second phase is characterized by simultaneous enthalpic and entropic gains. This phase improves the binding affinity 25-fold. The third phase represents the collapse of the trend and is triggered by the introduction of chemical functionalities larger than the binding cavity itself [CH(CH(3))(2)]. It is characterized by large enthalpy and affinity losses. The thermodynamic signatures associated with each phase provide guidelines for lead optimization.
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Affiliation(s)
- Yuko Kawasaki
- Department of Biology, Johns Hopkins University, Baltimore MD 21218
| | - Eduardo E. Chufan
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Virginie Lafont
- Department of Biology, Johns Hopkins University, Baltimore MD 21218
| | - Koushi Hidaka
- Department of Medicinal Chemistry, Center for Frontier Research in Medicinal Science, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan
| | - Yoshiaki Kiso
- Department of Medicinal Chemistry, Center for Frontier Research in Medicinal Science, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan
| | - L. Mario Amzel
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Ernesto Freire
- Department of Biology, Johns Hopkins University, Baltimore MD 21218
,Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
,Corresponding author: Department of Biology, The Johns Hopkins University, 3400 North Charles, Baltimore, MD 21218; Phone: (410) 516-7743, Fax: (410) 516-6469;
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