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Cernuda B, Fernandes CT, Allam SM, Orzillo M, Suppa G, Chia Chang Z, Athanasopoulos D, Buraei Z. The molecular determinants of R-roscovitine block of hERG channels. PLoS One 2019; 14:e0217733. [PMID: 31479461 PMCID: PMC6719874 DOI: 10.1371/journal.pone.0217733] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 08/17/2019] [Indexed: 02/06/2023] Open
Abstract
Human ether-à-go-go-related gene (Kv11.1, or hERG) is a potassium channel that conducts the delayed rectifier potassium current (IKr) during the repolarization phase of cardiac action potentials. hERG channels have a larger pore than other K+channels and can trap many unintended drugs, often resulting in acquired LQTS (aLQTS). R-roscovitine is a cyclin-dependent kinase (CDK) inhibitor that induces apoptosis in colorectal, breast, prostate, multiple myeloma, other cancer cell lines, and tumor xenografts, in micromolar concentrations. It is well tolerated in phase II clinical trials. R-roscovitine inhibits open hERG channels but does not become trapped in the pore. Two-electrode voltage clamp recordings from Xenopus oocytes expressing wild-type (WT) or hERG pore mutant channels (T623A, S624A, Y652A, F656A) demonstrated that compared to WT hERG, T623A, Y652A, and F656A inhibition by 200 μM R-roscovitine was ~ 48%, 29%, and 73% weaker, respectively. In contrast, S624A hERG was inhibited more potently than WT hERG, with a ~ 34% stronger inhibition. These findings were further supported by the IC50 values, which were increased for T623A, Y652A and F656A (by ~5.5, 2.75, and 42 fold respectively) and reduced 1.3 fold for the S624A mutant. Our data suggest that while T623, Y652, and F656 are critical for R-roscovitine-mediated inhibition, S624 may not be. Docking studies further support our findings. Thus, R-roscovitine’s relatively unique features, coupled with its tolerance in clinical trials, could guide future drug screens.
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Affiliation(s)
- Bryan Cernuda
- Department of Biology, Pace University, New York, NY, United States of America
| | | | - Salma Mohamed Allam
- Department of Biology, Pace University, New York, NY, United States of America
| | - Matthew Orzillo
- Department of Biology, Pace University, New York, NY, United States of America
| | - Gabrielle Suppa
- Department of Biology, Pace University, New York, NY, United States of America
| | - Zuleen Chia Chang
- Department of Biology, Pace University, New York, NY, United States of America
| | | | - Zafir Buraei
- Department of Biology, Pace University, New York, NY, United States of America
- * E-mail:
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Ortiz E, Possani LD. Scorpion toxins to unravel the conundrum of ion channel structure and functioning. Toxicon 2018; 150:17-27. [DOI: 10.1016/j.toxicon.2018.04.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 03/24/2018] [Accepted: 04/29/2018] [Indexed: 01/11/2023]
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Huo J, Guo X, Lu Q, Qiang H, Liu P, Bai L, Huang CLH, Zhang Y, Ma A. NS1643 enhances ionic currents in a G604S-WT hERG co-expression system associated with long QT syndrome 2. Clin Exp Pharmacol Physiol 2017; 44:1125-1133. [PMID: 28741726 DOI: 10.1111/1440-1681.12820] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 06/27/2017] [Accepted: 07/17/2017] [Indexed: 12/19/2022]
Affiliation(s)
- JianHua Huo
- Department of Cardiovascular Medicine; First Affiliated Hospital of Xi'an Jiaotong University; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University); Ministry of Education; Xi'an Shaanxi China
| | - Xueyan Guo
- Shaanxi Provincial People's Hospital; Xi'an Shaanxi China
| | - Qun Lu
- Department of Cardiovascular Medicine; First Affiliated Hospital of Xi'an Jiaotong University; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University); Ministry of Education; Xi'an Shaanxi China
| | - Hua Qiang
- Department of Cardiovascular Medicine; First Affiliated Hospital of Xi'an Jiaotong University; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University); Ministry of Education; Xi'an Shaanxi China
| | - Ping Liu
- Department of Cardiovascular Medicine; First Affiliated Hospital of Xi'an Jiaotong University; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University); Ministry of Education; Xi'an Shaanxi China
| | - Ling Bai
- Department of Cardiovascular Medicine; First Affiliated Hospital of Xi'an Jiaotong University; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University); Ministry of Education; Xi'an Shaanxi China
| | | | - Yanmin Zhang
- Department of Pediatric Cardiology; Childrens Research Institute; affiliate children's hospital of Xi'an Jiaotong University; Xi'an Shaanxi China
| | - Aiqun Ma
- Department of Cardiovascular Medicine; First Affiliated Hospital of Xi'an Jiaotong University; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University); Ministry of Education; Xi'an Shaanxi China
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Beaugrand M, Arnold AA, Bourgault S, Williamson PTF, Marcotte I. Comparative study of the structure and interaction of the pore helices of the hERG and Kv1.5 potassium channels in model membranes. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2017; 46:549-559. [PMID: 28314880 DOI: 10.1007/s00249-017-1201-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 02/15/2017] [Accepted: 02/17/2017] [Indexed: 10/19/2022]
Abstract
The hERG channel is a voltage-gated potassium channel found in cardiomyocytes that contributes to the repolarization of the cell membrane following the cardiac action potential, an important step in the regulation of the cardiac cycle. The lipids surrounding K+ channels have been shown to play a key role in their regulation, with anionic lipids shown to alter gating properties. In this study, we investigate how anionic lipids interact with the pore helix of hERG and compare the results with those from Kv1.5, which possesses a pore helix more typical of K+ channels. Circular dichroism studies of the pore helix secondary structure reveal that the presence of the anionic lipid DMPS within the bilayer results in a slight unfolding of the pore helices from both hERG and Kv1.5, albeit to a lesser extent for Kv1.5. In the presence of anionic lipids, the two pore helices exhibit significantly different interactions with the lipid bilayer. We demonstrate that the pore helix from hERG causes significant perturbation to the order in lipid bicelles, which contrasts with only small changes observed for Kv1.5. These observations suggest that the atypical sequence of the pore helix of hERG may play a key role in determining how anionic lipids influence its gating.
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Affiliation(s)
- Maïwenn Beaugrand
- Department of Chemistry, Université du Québec à Montréal, Downtown Station, PO Box 8888, Montreal, H3C 3P8, Canada
| | - Alexandre A Arnold
- Department of Chemistry, Université du Québec à Montréal, Downtown Station, PO Box 8888, Montreal, H3C 3P8, Canada
| | - Steve Bourgault
- Department of Chemistry, Université du Québec à Montréal, Downtown Station, PO Box 8888, Montreal, H3C 3P8, Canada
| | - Philip T F Williamson
- School of Biological Sciences, Highfield Campus, University of Southampton, Southampton, SO17 1BJ, UK
| | - Isabelle Marcotte
- Department of Chemistry, Université du Québec à Montréal, Downtown Station, PO Box 8888, Montreal, H3C 3P8, Canada.
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Conservation analysis of residues in the S4-S5 linker and the terminal part of the S5-P-S6 pore modulus in Kv and HCN channels: flexible determinants for the electromechanical coupling. Pflugers Arch 2014; 467:2069-79. [PMID: 25398373 DOI: 10.1007/s00424-014-1647-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 11/03/2014] [Indexed: 12/22/2022]
Abstract
Protein mobility is important to achieve protein function. Intrinsic flexibility associated with motion underlies this important issue and the analysis of side chain flexibility gives insights to understand it. In this work, the S5-P-S6 pore modulus (PM) of members of Kv and HCN channels was examined by a combination of sequence alignment, residue composition analysis, and intrinsic side chain flexibility. The PM sequences were organized as a database that was used to reveal and correlate the functional diversity of each analyzed family. Specifically, we focused our attention on the crucial role of the S4-S5 linker and its well-described interaction with the S6 T during the electromechanical coupling. Our analysis suggests the presence of a Gly-hinge in the middle of the S4-S5 linkers. This apparent Gly-hinge links a flexible N-terminal segment with a rigid C-terminal one, although in Kv7 channels, the latter segment is even more flexible. Instead, HCN channels exhibit a putative Thr-hinge and is rich in aromatic residues, in consequence, their linker is more rigid. Concerning S6, we confirm the presence of the two flexible kinks previously described and we provide the complete segmental flexibility profiles for the different families. Our results are discussed in terms of the relation between residue composition, conservation, and local conformational flexibility. This provides important insights to understand and differentiate the characteristic gating properties of these channels as well as their implications in cell physiology.
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Li Q, Wong YL, Ng HQ, Gayen S, Kang C. Structural insight into the transmembrane segments 3 and 4 of the hERG potassium channel. J Pept Sci 2014; 20:935-44. [PMID: 25331429 DOI: 10.1002/psc.2704] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 08/26/2014] [Accepted: 09/11/2014] [Indexed: 12/27/2022]
Abstract
The hERG (human ether-a-go-go related gene) potassium channel is a voltage-gated potassium channel containing an N-terminal domain, a voltage-sensor domain, a pore domain and a C-terminal domain. The transmembrane segment 4 (S4) is important for sensing changes of membrane potentials through positively charge residues. A construct containing partial S2-S3 linker, S3, S4 and the S4-S5 linker of the hERG channel was purified into detergent micelles. This construct exhibits good quality NMR spectrum when it was purified in lyso-myristoyl phosphatidylglycerol (LMPG) micelles. Structural study showed that S3 contains two short helices with a negatively charged surface. The S4 and S4-S5 linker adopt helical structures. The six positively charged residues in S4 localize at different sides, suggesting that they may have different functions in channel gating. Relaxation studies indicated that S3 is more flexible than S4. The boundaries of S3-S4 and S4-S4-S5 linker were identified. Our results provided structural information of the S3 and S4, which will be helpful to understand their roles in channel gating.
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Affiliation(s)
- Qingxin Li
- Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
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Insight into the molecular interaction between the cyclic nucleotide-binding homology domain and the eag domain of the hERG channel. FEBS Lett 2014; 588:2782-8. [PMID: 24931372 DOI: 10.1016/j.febslet.2014.05.056] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 05/14/2014] [Accepted: 05/27/2014] [Indexed: 12/18/2022]
Abstract
The gating of the hERG channel is regulated by its eag domain through molecular interaction with either the cyclic nucleotide-binding homology domain (CNBHD) or the linker between transmembrane segments 4 and 5. Our NMR study on the purified CNBHD demonstrated that it contains nine β-strands and does not bind cAMP. We show that the eag domain binds to the CBND through an interface containing several disease-associated mutations. The N-terminal cap domain and R56 in the eag domain are important for the interaction with the CNBHD. Residues from the CNBHD that were affected by the interaction with the eag domain were also identified. A R56Q mutation does not cause major structural changes in the eag domain and showed reduced interaction with the CNBHD.
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Li Q, Ng HQ, Yoon HS, Kang C. Solution structure of the cyclic-nucleotide binding homology domain of a KCNH channel. J Struct Biol 2014; 186:68-74. [PMID: 24632450 DOI: 10.1016/j.jsb.2014.03.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 03/03/2014] [Accepted: 03/10/2014] [Indexed: 12/28/2022]
Abstract
The carboxy-terminal region of the KCNH family of potassium channels contains a cyclic-nucleotide binding homology domain (CNBHD) that is important for channel gating and trafficking. The solution structure of the CNBHD of the KCNH potassium of zebrafish was determined using solution NMR spectroscopy. This domain exists as a monomer under solution conditions and adopts a similar fold to that determined by X-ray crystallography. The CNBHD does not bind cAMP because residue Y740 blocks the entry of cyclic-nucleotide to the binding pocket. Relaxation results show that the CNBHD is rigid except that some residues in the loop between β6 and β7 are flexible. Our results will be useful to understand the gating mechanism of KCNH family members through the CNBHD.
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Affiliation(s)
- Qingxin Li
- Institute of Chemical & Engineering Sciences, Agency for Science, Technology and Research (A∗STAR), Singapore 627833, Singapore
| | - Hui Qi Ng
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A∗STAR), Singapore 138669, Singapore
| | - Ho Sup Yoon
- Division of Structural Biology and Biochemistry, School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637511, Singapore
| | - Congbao Kang
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A∗STAR), Singapore 138669, Singapore.
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Durdagi S, Randall T, Duff HJ, Chamberlin A, Noskov SY. Rehabilitating drug-induced long-QT promoters: in-silico design of hERG-neutral cisapride analogues with retained pharmacological activity. BMC Pharmacol Toxicol 2014; 15:14. [PMID: 24606761 PMCID: PMC4016140 DOI: 10.1186/2050-6511-15-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 02/24/2014] [Indexed: 02/05/2023] Open
Abstract
Background The human ether-a-go-go related gene 1 (hERG1), which codes for a potassium ion channel, is a key element in the cardiac delayed rectified potassium current, IKr, and plays an important role in the normal repolarization of the heart’s action potential. Many approved drugs have been withdrawn from the market due to their prolongation of the QT interval. Most of these drugs have high potencies for their principal targets and are often irreplaceable, thus “rehabilitation” studies for decreasing their high hERG1 blocking affinities, while keeping them active at the binding sites of their targets, have been proposed to enable these drugs to re-enter the market. Methods In this proof-of-principle study, we focus on cisapride, a gastroprokinetic agent withdrawn from the market due to its high hERG1 blocking affinity. Here we tested an a priori strategy to predict a compound’s cardiotoxicity using de novo drug design with molecular docking and Molecular Dynamics (MD) simulations to generate a strategy for the rehabilitation of cisapride. Results We focused on two key receptors, a target interaction with the (adenosine) receptor and an off-target interaction with hERG1 channels. An analysis of the fragment interactions of cisapride at human A2A adenosine receptors and hERG1 central cavities helped us to identify the key chemical groups responsible for the drug activity and hERG1 blockade. A set of cisapride derivatives with reduced cardiotoxicity was then proposed using an in-silico two-tier approach. This set was compared against a large dataset of commercially available cisapride analogs and derivatives. Conclusions An interaction decomposition of cisapride and cisapride derivatives allowed for the identification of key active scaffolds and functional groups that may be responsible for the unwanted blockade of hERG1.
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Affiliation(s)
- Serdar Durdagi
- Centre for Molecular Simulations and Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
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Gravel AE, Arnold AA, Dufourc EJ, Marcotte I. An NMR investigation of the structure, function and role of the hERG channel selectivity filter in the long QT syndrome. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1494-502. [DOI: 10.1016/j.bbamem.2013.02.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 02/23/2013] [Accepted: 02/25/2013] [Indexed: 02/03/2023]
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