1
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Chuntakaruk H, Hengphasatporn K, Shigeta Y, Aonbangkhen C, Lee VS, Khotavivattana T, Rungrotmongkol T, Hannongbua S. FMO-guided design of darunavir analogs as HIV-1 protease inhibitors. Sci Rep 2024; 14:3639. [PMID: 38351065 PMCID: PMC10864397 DOI: 10.1038/s41598-024-53940-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Accepted: 02/06/2024] [Indexed: 02/16/2024] Open
Abstract
The prevalence of HIV-1 infection continues to pose a significant global public health issue, highlighting the need for antiretroviral drugs that target viral proteins to reduce viral replication. One such target is HIV-1 protease (PR), responsible for cleaving viral polyproteins, leading to the maturation of viral proteins. While darunavir (DRV) is a potent HIV-1 PR inhibitor, drug resistance can arise due to mutations in HIV-1 PR. To address this issue, we developed a novel approach using the fragment molecular orbital (FMO) method and structure-based drug design to create DRV analogs. Using combinatorial programming, we generated novel analogs freely accessible via an on-the-cloud mode implemented in Google Colab, Combined Analog generator Tool (CAT). The designed analogs underwent cascade screening through molecular docking with HIV-1 PR wild-type and major mutations at the active site. Molecular dynamics (MD) simulations confirmed the assess ligand binding and susceptibility of screened designed analogs. Our findings indicate that the three designed analogs guided by FMO, 19-0-14-3, 19-8-10-0, and 19-8-14-3, are superior to DRV and have the potential to serve as efficient PR inhibitors. These findings demonstrate the effectiveness of our approach and its potential to be used in further studies for developing new antiretroviral drugs.
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Affiliation(s)
- Hathaichanok Chuntakaruk
- Program in Bioinformatics and Computational Biology, Graduate School, Chulalongkorn University, Bangkok, 10330, Thailand
- Center of Excellence in Structural and Computational Biology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Kowit Hengphasatporn
- Center for Computational Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan.
| | - Yasuteru Shigeta
- Center for Computational Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan
| | - Chanat Aonbangkhen
- Center of Excellence in Natural Products Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Vannajan Sanghiran Lee
- Chemistry Department, Faculty of Science, University Malaya, Kuala Lumpur, 50603, Malaysia
| | - Tanatorn Khotavivattana
- Center of Excellence in Natural Products Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
| | - Thanyada Rungrotmongkol
- Program in Bioinformatics and Computational Biology, Graduate School, Chulalongkorn University, Bangkok, 10330, Thailand.
- Center of Excellence in Structural and Computational Biology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
| | - Supot Hannongbua
- Center of Excellence in Computational Chemistry (CECC), Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
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2
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Wong-Sam A, Wang YF, Kneller DW, Kovalevsky AY, Ghosh AK, Harrison RW, Weber IT. HIV-1 protease with 10 lopinavir and darunavir resistance mutations exhibits altered inhibition, structural rearrangements and extreme dynamics. J Mol Graph Model 2022; 117:108315. [PMID: 36108568 PMCID: PMC10091457 DOI: 10.1016/j.jmgm.2022.108315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/17/2022] [Accepted: 08/21/2022] [Indexed: 01/14/2023]
Abstract
Antiretroviral drug resistance is a therapeutic obstacle for people with HIV. HIV protease inhibitors darunavir and lopinavir are recommended for resistant infections. We characterized a protease mutant (PR10x) derived from a highly resistant clinical isolate including 10 mutations associated with resistance to lopinavir and darunavir. Compared to the wild-type protease, PR10x exhibits ∼3-fold decrease in catalytic efficiency and Ki values of 2-3 orders of magnitude worse for darunavir, lopinavir, and potent investigational inhibitor GRL-519. Crystal structures of the mutant were solved in a ligand-free form and in complex with GRL-519. The structures show altered interactions in the active site, flap-core interface, hydrophobic core, hinge region, and 80s loop compared to the corresponding wild-type protease structures. The ligand-free crystal structure exhibits a highly curled flap conformation which may amplify drug resistance. Molecular dynamics simulations performed for 1 μs on ligand-free dimers showed extremely large fluctuations in the flaps for PR10x compared to equivalent simulations on PR with a single L76V mutation or wild-type protease. This analysis offers insight about the synergistic effects of mutations in highly resistant variants.
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Affiliation(s)
- Andres Wong-Sam
- Department of Biology, Georgia State University, Atlanta, GA, 30303, USA
| | - Yuan-Fang Wang
- Department of Biology, Georgia State University, Atlanta, GA, 30303, USA
| | - Daniel W Kneller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Andrey Y Kovalevsky
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Arun K Ghosh
- Department of Chemistry and Department of Medicinal Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Robert W Harrison
- Department of Biology, Georgia State University, Atlanta, GA, 30303, USA; Department of Computer Science, Georgia State University, Atlanta, GA, 30303, USA
| | - Irene T Weber
- Department of Biology, Georgia State University, Atlanta, GA, 30303, USA; Department of Chemistry, Georgia State University, Atlanta, GA, 30303, USA.
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3
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Hu S, Ma L, Dong B, Shan Q, Zhou J, Zhang G, Wang M, Cen S, Zhu M, Wang J, Wang Y. A kind of HIV-1 protease inhibitors containing phenols with antiviral activity against DRV-resistant variants. Bioorg Med Chem 2022; 64:116760. [PMID: 35483138 DOI: 10.1016/j.bmc.2022.116760] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/15/2022] [Accepted: 04/18/2022] [Indexed: 11/30/2022]
Abstract
Based upon the preliminary design of enhancing genetic barrier to drug-resistant viral mutants by maximizing hydrogen-bonding or other van der Waals contacts, we have designed, synthesized and biologically evaluated a new class of HIV-1 protease inhibitors with phenol derived P2 ligands and nitro or halogens in P2' ligands. Results indicate that a majority of inhibitors exhibit robust enzyme inhibitory with IC50 values in picomolar or single digit nanomolar ranges. Among which, compound 17d displays potency with IC50 value of 21 pM and high protease selectivity. Of note, 17d exhibits greater antiviral activity against the DRV-resistant variant than the efficacy against the wild type virus. Furthermore, the molecular modeling studies demonstrate important interactions between 17d and the active sites of both the wild-type and DRV-resistant HIV-1 protease, as well as furnish insights for further optimization of new inhibitors.
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Affiliation(s)
- Shangjiu Hu
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China
| | - Ling Ma
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China
| | - Biao Dong
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China
| | - Qi Shan
- Tianjin Institute of Pharmaceutical Research, Tianjin 300462, China
| | - Jinming Zhou
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Department of Chemistry, Zhejiang Normal University, Jinhua 321004, China
| | - Guoning Zhang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China
| | - Minghua Wang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China
| | - Shan Cen
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China
| | - Mei Zhu
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China.
| | - Juxian Wang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China.
| | - Yucheng Wang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China.
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4
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Weber IT, Wang YF, Harrison RW. HIV Protease: Historical Perspective and Current Research. Viruses 2021; 13:v13050839. [PMID: 34066370 PMCID: PMC8148205 DOI: 10.3390/v13050839] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/01/2021] [Accepted: 05/03/2021] [Indexed: 12/15/2022] Open
Abstract
The retroviral protease of human immunodeficiency virus (HIV) is an excellent target for antiviral inhibitors for treating HIV/AIDS. Despite the efficacy of therapy, current efforts to control the disease are undermined by the growing threat posed by drug resistance. This review covers the historical background of studies on the structure and function of HIV protease, the subsequent development of antiviral inhibitors, and recent studies on drug-resistant protease variants. We highlight the important contributions of Dr. Stephen Oroszlan to fundamental knowledge about the function of the HIV protease and other retroviral proteases. These studies, along with those of his colleagues, laid the foundations for the design of clinical inhibitors of HIV protease. The drug-resistant protease variants also provide an excellent model for investigating the molecular mechanisms and evolution of resistance.
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Affiliation(s)
- Irene T. Weber
- Department of Biology, Georgia State University, Atlanta, GA 30302, USA;
- Correspondence:
| | - Yuan-Fang Wang
- Department of Biology, Georgia State University, Atlanta, GA 30302, USA;
| | - Robert W. Harrison
- Department of Computer Science, Georgia State University, Atlanta, GA 30302, USA;
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5
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Ibba R, Piras S, Corona P, Riu F, Loddo R, Delogu I, Collu G, Sanna G, Caria P, Dettori T, Carta A. Synthesis, Antitumor and Antiviral In Vitro Activities of New Benzotriazole-Dicarboxamide Derivatives. Front Chem 2021; 9:660424. [PMID: 34017818 PMCID: PMC8129498 DOI: 10.3389/fchem.2021.660424] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/19/2021] [Indexed: 12/17/2022] Open
Abstract
Cancer and viral infections continue to threaten humankind causing death worldwide. Hence, the discovery of new anticancer and antiviral agents still represents a major scientific goal. Heterocycles designed to mimic the chemical structure of natural pyrimidines and purines have been designed over the years, exerting their activity acting as false substrates on several different targets. We reported a series of bis-benzotriazole-dicarboxamide derivatives which inhibit viral helicase of poliovirus, and hence we planned structure modifications to obtain different series of new dicarboxamides. Here, the synthesis and characterization of 56 new compounds: 31 bis-benzotriazole dicarboxamides and 25 mono-substituted acidic derivatives are reported. The synthesized compounds were tested for their antiviral and antitumor activity. Mostly, compounds 4a, 4c and 4d showed antiviral activity against tested Picornaviruses, Coxsackievirus B5 and Poliovirus-1. Likewise, four derivatives (3b, 3d, 4d, 9b) showed notable antiproliferative activity inhibiting cell growth in two distinct antitumor screenings. Compound 3b was selected as the antitumor lead compound for the wide range of activity and the potency proved. The lead compound was proved to induce apoptosis in SK-MES1 tumor cells, in a dose-dependent manner.
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Affiliation(s)
- Roberta Ibba
- Department of Chemistry and Pharmacy, University of Sassari, Sassari, Italy
| | - Sandra Piras
- Department of Chemistry and Pharmacy, University of Sassari, Sassari, Italy
| | - Paola Corona
- Department of Chemistry and Pharmacy, University of Sassari, Sassari, Italy
| | - Federico Riu
- Department of Chemistry and Pharmacy, University of Sassari, Sassari, Italy
| | - Roberta Loddo
- Department of Biomedical Sciences, Section of Microbiology and Virology, University of Cagliari, Cittadella Universitaria, Cagliari, Italy
| | - Ilenia Delogu
- Department of Biomedical Sciences, Section of Microbiology and Virology, University of Cagliari, Cittadella Universitaria, Cagliari, Italy
| | - Gabriella Collu
- Department of Biomedical Sciences, Section of Microbiology and Virology, University of Cagliari, Cittadella Universitaria, Cagliari, Italy
| | - Giuseppina Sanna
- Department of Biomedical Sciences, Section of Microbiology and Virology, University of Cagliari, Cittadella Universitaria, Cagliari, Italy
| | - Paola Caria
- Department of Biomedical Sciences, Section of Biochemistry, Biology and Genetics, University of Cagliari, Cittadella Universitaria, Cagliari, Italy
| | - Tinuccia Dettori
- Department of Biomedical Sciences, Section of Biochemistry, Biology and Genetics, University of Cagliari, Cittadella Universitaria, Cagliari, Italy
| | - Antonio Carta
- Department of Chemistry and Pharmacy, University of Sassari, Sassari, Italy
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Ma R, Ding Y, Chen R, Wang Z, Wang L, Ma Y. Oxidant/Solvent-Controlled I 2-Catalyzed Domino Annulation for Selective Synthesis of 2-Aroylbenzothiazoles and 2-Arylbenzothiazoles under Metal-Free Conditions. J Org Chem 2020; 86:310-321. [PMID: 33332126 DOI: 10.1021/acs.joc.0c02095] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A simple and practical domino protocol for the selective synthesis of 2-aroylbenzothiazoles and 2-aryl benzothiazoles catalyzed by I2 is developed under metal-free conditions. The reaction outcomes are exclusively controlled by the reaction oxidant/medium. With DMSO employed as both the solvent and the oxidant, an oxidation of aromatic methyl ketones takes precedence over the condensation with 2-aminobenzenethiols. On the other hand, when the reaction was carried out in PhNO2 or in 1,4-dioxane containing PhNO2, the condensation of aromatic methyl ketones with 2-aminobenzenethiols has priority to form imines which is followed by an oxidation of the methyl group from ketones to afford 2-arylbenzothiazoles as a sole product. The PhNO2/I2 co-catalytic system is proposed first time.
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Affiliation(s)
- Renchao Ma
- Institute of Advanced Studies and School of Pharmaceutical and Chemical Engineering, Taizhou University, Taizhou 318000, P R China
| | - Yuxin Ding
- Institute of Advanced Studies and School of Pharmaceutical and Chemical Engineering, Taizhou University, Taizhou 318000, P R China
| | - Rener Chen
- Institute of Advanced Studies and School of Pharmaceutical and Chemical Engineering, Taizhou University, Taizhou 318000, P R China
| | - Zhiming Wang
- Institute of Advanced Studies and School of Pharmaceutical and Chemical Engineering, Taizhou University, Taizhou 318000, P R China
| | - Lei Wang
- Institute of Advanced Studies and School of Pharmaceutical and Chemical Engineering, Taizhou University, Taizhou 318000, P R China
| | - Yongmin Ma
- Institute of Advanced Studies and School of Pharmaceutical and Chemical Engineering, Taizhou University, Taizhou 318000, P R China
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7
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Soumia M, Hanane Z, Benaissa M, Younes FZ, Chakib A, Mohammed B, Mohamed B. Towards potential inhibitors of COVID-19 main protease Mpro by virtual screening and molecular docking study. JOURNAL OF TAIBAH UNIVERSITY FOR SCIENCE 2020. [DOI: 10.1080/16583655.2020.1850002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Moujane Soumia
- Biochemistry of natural substances, Faculty of Science and Techniques, Moulay Ismail University, Errachdia, Morocco
| | - Zaki Hanane
- Molecular Chemistry and Natural Substances Laboratory, Faculty of Science, Moulay Ismail University, Meknes, Morocco
- EST Khenifra, Sultan Moulay Sliman University, Khenifra, Morocco
| | - Moualij Benaissa
- Biochemistry of natural substances, Faculty of Science and Techniques, Moulay Ismail University, Errachdia, Morocco
| | - Filali Zegzouti Younes
- LABASE Laboratory, Faculty of Science of Meknes, Moulay Ismail University, Meknes, Morocco
- Health & Environment Skills Cluster, Moulay Ismail University, Meknes, Morocco
| | - Alem Chakib
- Biochemistry of natural substances, Faculty of Science and Techniques, Moulay Ismail University, Errachdia, Morocco
| | - Bouachrine Mohammed
- Molecular Chemistry and Natural Substances Laboratory, Faculty of Science, Moulay Ismail University, Meknes, Morocco
- EST Khenifra, Sultan Moulay Sliman University, Khenifra, Morocco
| | - Benlyas Mohamed
- Biochemistry of natural substances, Faculty of Science and Techniques, Moulay Ismail University, Errachdia, Morocco
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8
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Darunavir-Resistant HIV-1 Protease Constructs Uphold a Conformational Selection Hypothesis for Drug Resistance. Viruses 2020; 12:v12111275. [PMID: 33171603 PMCID: PMC7695139 DOI: 10.3390/v12111275] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 10/23/2020] [Accepted: 10/30/2020] [Indexed: 01/24/2023] Open
Abstract
Multidrug resistance continues to be a barrier to the effectiveness of highly active antiretroviral therapy in the treatment of human immunodeficiency virus 1 (HIV-1) infection. Darunavir (DRV) is a highly potent protease inhibitor (PI) that is oftentimes effective when drug resistance has emerged against first-generation inhibitors. Resistance to darunavir does evolve and requires 10–20 amino acid substitutions. The conformational landscapes of six highly characterized HIV-1 protease (PR) constructs that harbor up to 19 DRV-associated mutations were characterized by distance measurements with pulsed electron double resonance (PELDOR) paramagnetic resonance spectroscopy, namely double electron–electron resonance (DEER). The results show that the accumulated substitutions alter the conformational landscape compared to PI-naïve protease where the semi-open conformation is destabilized as the dominant population with open-like states becoming prevalent in many cases. A linear correlation is found between values of the DRV inhibition parameter Ki and the open-like to closed-state population ratio determined from DEER. The nearly 50% decrease in occupancy of the semi-open conformation is associated with reduced enzymatic activity, characterized previously in the literature.
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9
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Bulut H, Hattori SI, Aoki-Ogata H, Hayashi H, Das D, Aoki M, Davis DA, Rao KV, Nyalapatla PR, Ghosh AK, Mitsuya H. Single atom changes in newly synthesized HIV protease inhibitors reveal structural basis for extreme affinity, high genetic barrier, and adaptation to the HIV protease plasticity. Sci Rep 2020; 10:10664. [PMID: 32606378 PMCID: PMC7326966 DOI: 10.1038/s41598-020-65993-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 04/15/2020] [Indexed: 11/30/2022] Open
Abstract
HIV-1 protease inhibitors (PIs), such as darunavir (DRV), are the key component of antiretroviral therapy. However, HIV-1 often acquires resistance to PIs. Here, seven novel PIs were synthesized, by introducing single atom changes such as an exchange of a sulfur to an oxygen, scission of a single bond in P2′-cyclopropylaminobenzothiazole (or -oxazole), and/or P1-benzene ring with fluorine scan of mono- or bis-fluorine atoms around DRV’s scaffold. X-ray structural analyses of the PIs complexed with wild-type Protease (PRWT) and highly-multi-PI-resistance-associated PRDRVRP51 revealed that the PIs better adapt to structural plasticity in PR with resistance-associated amino acid substitutions by formation of optimal sulfur bond and adaptation of cyclopropyl ring in the S2′-subsite. Furthermore, these PIs displayed increased cell permeability and extreme anti-HIV-1 potency compared to DRV. Our work provides the basis for developing novel PIs with high potency against PI-resistant HIV-1 variants with a high genetic barrier.
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Affiliation(s)
- Haydar Bulut
- HIV and AIDS Malignancy Branch, National Cancer Institute, National Institutes of Health, Bethesda, 20892, MD, United States
| | - Shin-Ichiro Hattori
- Department of Refractory Viral Infections, National Center for Global Health and Medicine Research Institute, Tokyo, 162-8655, Japan
| | - Hiromi Aoki-Ogata
- HIV and AIDS Malignancy Branch, National Cancer Institute, National Institutes of Health, Bethesda, 20892, MD, United States
| | - Hironori Hayashi
- Department of Refractory Viral Infections, National Center for Global Health and Medicine Research Institute, Tokyo, 162-8655, Japan.,Department of Intelligent Network for Infection Control, Tohoku University Graduate School of Medicine, 2-1, Seiryo-machi, Aoba-ku, 980-8575, Sendai, Miyagi, Japan
| | - Debananda Das
- HIV and AIDS Malignancy Branch, National Cancer Institute, National Institutes of Health, Bethesda, 20892, MD, United States
| | - Manabu Aoki
- HIV and AIDS Malignancy Branch, National Cancer Institute, National Institutes of Health, Bethesda, 20892, MD, United States
| | - David A Davis
- HIV and AIDS Malignancy Branch, National Cancer Institute, National Institutes of Health, Bethesda, 20892, MD, United States
| | - Kalapala Venkateswara Rao
- Department of Chemistry and Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, 47907, IN, United States
| | - Prasanth R Nyalapatla
- Department of Chemistry and Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, 47907, IN, United States
| | - Arun K Ghosh
- Department of Chemistry and Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, 47907, IN, United States
| | - Hiroaki Mitsuya
- HIV and AIDS Malignancy Branch, National Cancer Institute, National Institutes of Health, Bethesda, 20892, MD, United States. .,Department of Refractory Viral Infections, National Center for Global Health and Medicine Research Institute, Tokyo, 162-8655, Japan. .,Department of Clinical Sciences, Kumamoto University Hospital, Kumamoto, 860-8556, Japan.
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10
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Sun Z, Xu Y, Zhang D, McDermott AE. Probing allosteric coupling in a constitutively open mutant of the ion channel KcsA using solid-state NMR. Proc Natl Acad Sci U S A 2020; 117:7171-7175. [PMID: 32188782 PMCID: PMC7132268 DOI: 10.1073/pnas.1908828117] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Transmembrane allosteric coupling is a feature of many critical biological signaling events. Here we test whether transmembrane allosteric coupling controls the potassium binding affinity of the prototypical potassium channel KcsA in the context of C-type inactivation. Activation of KcsA is initiated by proton binding to the pH gate upon an intracellular drop in pH. Numerous studies have suggested that this proton binding also prompts a conformational switch, leading to a loss of affinity for potassium ions at the selectivity filter and therefore to channel inactivation. We tested this mechanism for inactivation using a KcsA mutant (H25R/E118A) that exhibits an open pH gate across a broad range of pH values. We present solid-state NMR measurements of this open mutant at neutral pH to probe the affinity for potassium at the selectivity filter. The potassium binding affinity in the selectivity filter of this mutant, 81 mM, is about four orders of magnitude weaker than that of wild-type KcsA at neutral pH and is comparable to the value for wild-type KcsA at low pH (pH ≈ 3.5). This result strongly supports our assertion that the open pH gate allosterically affects the potassium binding affinity of the selectivity filter. In this mutant, the protonation state of a glutamate residue (E120) in the pH sensor is sensitive to potassium binding, suggesting that this mutant also has flexibility in the activation gate and is subject to transmembrane allostery.
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Affiliation(s)
- Zhiyu Sun
- Department of Chemistry, Columbia University, New York, NY 10027
| | - Yunyao Xu
- Department of Chemistry, Columbia University, New York, NY 10027
| | - Dongyu Zhang
- Department of Chemistry, Columbia University, New York, NY 10027
| | - Ann E McDermott
- Department of Chemistry, Columbia University, New York, NY 10027
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