1
|
Conformational changes upon gating of KirBac1.1 into an open-activated state revealed by solid-state NMR and functional assays. Proc Natl Acad Sci U S A 2020; 117:2938-2947. [PMID: 31980523 PMCID: PMC7022178 DOI: 10.1073/pnas.1915010117] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Inward rectifier K+ (Kir) channels play an important role in reestablishing the resting membrane state of the action potential of excitable cells in humans. KirBac1.1 is a prokaryotic Kir channel with a high degree of homology to human Kir channels and can be isotopically labeled in NMR quantities for structural studies. Functional assays and NMR assignments confirm that KirBac1.1 is in a constitutively conductive state. Solid-state NMR assignments further reveal alternate conformations at key sites in the protein that are well conserved through human Kir channels, hinting at a possible allosteric network between channels. These underlying sequential and structural motifs could explain abnormal conductive properties of these channels fundamental to their native gating processes. The conformational changes required for activation and K+ conduction in inward-rectifier K+ (Kir) channels are still debated. These structural changes are brought about by lipid binding. It is unclear how this process relates to fast gating or if the intracellular and extracellular regions of the protein are coupled. Here, we examine the structural details of KirBac1.1 reconstituted into both POPC and an activating lipid mixture of 3:2 POPC:POPG (wt/wt). KirBac1.1 is a prokaryotic Kir channel that shares homology with human Kir channels. We establish that KirBac1.1 is in a constitutively active state in POPC:POPG bilayers through the use of real-time fluorescence quenching assays and Förster resonance energy transfer (FRET) distance measurements. Multidimensional solid-state NMR (SSNMR) spectroscopy experiments reveal two different conformers within the transmembrane regions of the protein in this activating lipid environment, which are distinct from the conformation of the channel in POPC bilayers. The differences between these three distinct channel states highlight conformational changes associated with an open activation gate and suggest a unique allosteric pathway that ties the selectivity filter to the activation gate through interactions between both transmembrane helices, the turret, selectivity filter loop, and the pore helix. We also identify specific residues involved in this conformational exchange that are highly conserved among human Kir channels.
Collapse
|
2
|
Yang PC, Perissinotti LL, López-Redondo F, Wang Y, DeMarco KR, Jeng MT, Vorobyov I, Harvey RD, Kurokawa J, Noskov SY, Clancy CE. A multiscale computational modelling approach predicts mechanisms of female sex risk in the setting of arousal-induced arrhythmias. J Physiol 2017; 595:4695-4723. [PMID: 28516454 PMCID: PMC5509858 DOI: 10.1113/jp273142] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 04/24/2017] [Indexed: 01/10/2023] Open
Abstract
KEY POINTS This study represents a first step toward predicting mechanisms of sex-based arrhythmias that may lead to important developments in risk stratification and may inform future drug design and screening. We undertook simulations to reveal the conditions (i.e. pacing, drugs, sympathetic stimulation) required for triggering and sustaining reentrant arrhythmias. Using the recently solved cryo-EM structure for the Eag-family channel as a template, we revealed potential interactions of oestrogen with the pore loop hERG mutation (G604S). Molecular models suggest that oestrogen and dofetilide blockade can concur simultaneously in the hERG channel pore. ABSTRACT Female sex is a risk factor for inherited and acquired long-QT associated torsade de pointes (TdP) arrhythmias, and sympathetic discharge is a major factor in triggering TdP in female long-QT syndrome patients. We used a combined experimental and computational approach to predict 'the perfect storm' of hormone concentration, IKr block and sympathetic stimulation that induces arrhythmia in females with inherited and acquired long-QT. More specifically, we developed mathematical models of acquired and inherited long-QT syndrome in male and female ventricular human myocytes by combining effects of a hormone and a hERG blocker, dofetilide, or hERG mutations. These 'male' and 'female' model myocytes and tissues then were used to predict how various sex-based differences underlie arrhythmia risk in the setting of acute sympathetic nervous system discharge. The model predicted increased risk for arrhythmia in females when acute sympathetic nervous system discharge was applied in the settings of both inherited and acquired long-QT syndrome. Females were predicted to have protection from arrhythmia induction when progesterone is high. Males were protected by the presence of testosterone. Structural modelling points towards two plausible and distinct mechanisms of oestrogen action enhancing torsadogenic effects: oestradiol interaction with hERG mutations in the pore loop containing G604 or with common TdP-related blockers in the intra-cavity binding site. Our study presents findings that constitute the first evidence linking structure to function mechanisms underlying female dominance of arousal-induced arrhythmias.
Collapse
Affiliation(s)
- Pei-Chi Yang
- Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
| | - Laura L Perissinotti
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Alberta, Canada
| | - Fernando López-Redondo
- Department of Bio-informational Pharmacology, Medical Research Institute, Tokyo Medical and Dental University
| | - Yibo Wang
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Alberta, Canada
| | - Kevin R DeMarco
- Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
| | - Mao-Tsuen Jeng
- Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
| | - Igor Vorobyov
- Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
| | - Robert D Harvey
- Department of Pharmacology, University of Nevada, Reno, NV, USA
| | - Junko Kurokawa
- Department of Bio-informational Pharmacology, Medical Research Institute, Tokyo Medical and Dental University.,Department of Bio-informational Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Sergei Y Noskov
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Alberta, Canada
| | - Colleen E Clancy
- Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
| |
Collapse
|
3
|
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.
Collapse
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.
| |
Collapse
|
4
|
Li Y, Ng HQ, Li Q, Kang C. Structure of the Cyclic Nucleotide-Binding Homology Domain of the hERG Channel and Its Insight into Type 2 Long QT Syndrome. Sci Rep 2016; 6:23712. [PMID: 27025590 PMCID: PMC4812329 DOI: 10.1038/srep23712] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 03/14/2016] [Indexed: 01/09/2023] Open
Abstract
The human ether-à-go-go related gene (hERG) channel is crucial for the cardiac action potential by contributing to the fast delayed-rectifier potassium current. Mutations in the hERG channel result in type 2 long QT syndrome (LQT2). The hERG channel contains a cyclic nucleotide-binding homology domain (CNBHD) and this domain is required for the channel gating though molecular interactions with the eag domain. Here we present solution structure of the CNBHD of the hERG channel. The structural study reveals that the CNBHD adopts a similar fold to other KCNH channels. It is self-liganded and it contains a short β-strand that blocks the nucleotide-binding pocket in the β-roll. Folding of LQT2-related mutations in this domain was shown to be affected by point mutation. Mutations in this domain can cause protein aggregation in E. coli cells or induce conformational changes. One mutant-R752W showed obvious chemical shift perturbation compared with the wild-type, but it still binds to the eag domain. The helix region from the N-terminal cap domain of the hERG channel showed unspecific interactions with the CNBHD.
Collapse
Affiliation(s)
- Yan Li
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Hui Qi Ng
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Qingxin Li
- Institute of Chemical &Engineering Sciences, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - CongBao Kang
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| |
Collapse
|
5
|
Lubecka EA, Sikorska E, Sobolewski D, Prahl A, Slaninová J, Ciarkowski J. Potent antidiuretic agonists, deamino-vasopressin and desmopressin, and their inverso analogs: NMR structure and interactions with micellar and liposomic models of cell membrane. Biopolymers 2016; 106:245-59. [PMID: 26916937 DOI: 10.1002/bip.22825] [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: 09/07/2015] [Revised: 02/11/2016] [Accepted: 02/13/2016] [Indexed: 11/08/2022]
Abstract
Deamination of vasopressin (AVP) enhances its antidiuretic activity. Moreover, introduction of D-Arg8 instead of its L enantiomer in deamino-vasopressin (dAVP) results in an extremely potent and selective antidiuretic agonist - desmopressin (dDAVP). In this study we describe the synthesis, pharmacological properties and structures of these two potent antidiuretic agonists, and their inverso analogs. The structures of the peptides are studied in micellar and liposomic models of cell membrane using CD spectroscopy. Additionally, three-dimensional structures in mixed anionic-zwitterionic micelles are obtained using NMR spectroscopy supported by molecular dynamics simulations. Our conformational studies have shown that desmopressin in a membrane mimicking environment adopts one of the characteristic for vasopressin-like peptides β-turn - in position 3,4. Furthermore, dDAVP shows the tendency to create a β-turn in the Cys6-Gly9 C-tail, considered to be important for the antidiuretic activity, and also some tendency to adopt a 5,6 β-turn. In desmopressin, in contrast to the native vasopressin, deamino-vasopressin and [D-Arg8]-vasopressin (DAVP), the Arg8 side chain, crucial for the pressor and antidiuretic activities, is very well exposed for interaction with the receptor, whereas Gly9, crucial for the pressor and uterotonic activities, is situated together with the C-terminal amide group very close to the tocin ring. The arrangements of the Gln4 and Asn5 side chains, being crucial for OT activity, also differ in desmopressin as compared to those of AVP, dAVP and DAVP. These differences in arrangement of the important for activities side chains are likely to explain extremely potent and selective antidiuretic activities of desmopressin. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 245-259, 2016.
Collapse
Affiliation(s)
- Emilia A Lubecka
- Faculty of Chemistry, University of Gdańsk, Gdańsk, 80-308, Poland
| | - Emilia Sikorska
- Faculty of Chemistry, University of Gdańsk, Gdańsk, 80-308, Poland
| | | | - Adam Prahl
- Faculty of Chemistry, University of Gdańsk, Gdańsk, 80-308, Poland
| | - Jiřina Slaninová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10 Prague, Czech Republic
| | - Jerzy Ciarkowski
- Faculty of Chemistry, University of Gdańsk, Gdańsk, 80-308, Poland
| |
Collapse
|
6
|
Kanters JK, Skibsbye L, Hedley PL, Dembic M, Liang B, Hagen CM, Eschen O, Grunnet M, Christiansen M, Jespersen T. Combined gating and trafficking defect in Kv11.1 manifests as a malignant long QT syndrome phenotype in a large Danish p.F29L founder family. Scandinavian Journal of Clinical and Laboratory Investigation 2015; 75:699-709. [PMID: 26403377 DOI: 10.3109/00365513.2015.1091090] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Congenital long QT syndrome (LQTS) is a hereditary cardiac channelopathy characterized by delayed ventricular repolarization, syncope, torsades de pointes and sudden cardiac death. Thirty-three members of five apparently 'unrelated' Danish families carry the KCNH2:c.87C> A; p.F29L founder mutation. METHODS AND RESULTS Linkage disequilibrium mapping with microsatellites around KCNH2 enabled us to estimate the age of the founder mutation to be approximately 22 generations, corresponding to around 550 years. Neighbouring-Joining analysis disclosed one early and three later nodes. The median QTc time of the carriers was 490 ms (range: 415-589 ms) and no difference was seen between the different branches of the family. The mutation is malignant with a penetrance of 73%. Ten F29L carriers received implantable defibrillators (ICDs) (median age at implant 20 years), and of those four individuals experienced eight appropriate shocks. Patch-clamp analysis in HEK 293 cells, performed at 34°C disclosed a loss-of-function phenotype with fast deactivation, reduced steady-state inactivation current density and a positive voltage shift in inactivation. Western blotting of HEK 293 cells transfected with KCNH2:WT and KCNH2:c.87C> A revealed a reduced fraction of fully glycosylated hERG:p.F29L suggesting that this mutation results in defective trafficking. CONCLUSION The altered channel gating kinetics in combination with defective trafficking of mutated channels is expected to result in reduced repolarizing current density and, thus, a LQTS phenotype.
Collapse
Affiliation(s)
- Jørgen K Kanters
- a Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences , University of Copenhagen , Denmark.,b Department of Cardiology , Herlev and Gentofte Hospitals , Denmark
| | - Lasse Skibsbye
- a Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences , University of Copenhagen , Denmark
| | - Paula L Hedley
- c Department for Congenital Disorders , Statens Serum Institut , Denmark.,d MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University , Aarhus , Denmark
| | - Maja Dembic
- a Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences , University of Copenhagen , Denmark.,c Department for Congenital Disorders , Statens Serum Institut , Denmark
| | - Bo Liang
- a Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences , University of Copenhagen , Denmark
| | - Christian M Hagen
- a Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences , University of Copenhagen , Denmark.,c Department for Congenital Disorders , Statens Serum Institut , Denmark
| | - Ole Eschen
- e Department of Cardiology , Center for Cardiovascular Research, Aalborg Sygehus, Aarhus University Hospital , Aarhus , Denmark
| | - Morten Grunnet
- a Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences , University of Copenhagen , Denmark
| | - Michael Christiansen
- a Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences , University of Copenhagen , Denmark.,c Department for Congenital Disorders , Statens Serum Institut , Denmark
| | - Thomas Jespersen
- a Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences , University of Copenhagen , Denmark
| |
Collapse
|
7
|
Lubecka EA, Sikorska E, Sobolewski D, Prahl A, Slaninová J, Ciarkowski J. Arginine-, D-arginine-vasopressin, and their inverso analogues in micellar and liposomic models of cell membrane: CD, NMR, and molecular dynamics studies. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2015; 44:727-43. [PMID: 26290060 PMCID: PMC4628624 DOI: 10.1007/s00249-015-1071-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 07/22/2015] [Accepted: 08/03/2015] [Indexed: 01/21/2023]
Abstract
We describe the synthesis, pharmacological properties, and structures of antidiuretic agonists, arginine vasopressin (AVP) and [d-Arg8]-vasopressin (DAVP), and their inverso analogues. The structures of the peptides are studied based on micellar and liposomic models of cell membranes using CD spectroscopy. Additionally, three-dimensional structures in mixed anionic–zwitterionic micelles are obtained using NMR spectroscopy and molecular dynamics simulations. NMR data have shown that AVP and DAVP tend to adopt typical of vasopressin-like peptides β-turns: in the 2–5 and 3–6 fragments. The inverso-analogues also adopt β-turns in the 3–6 fragments. For this reason, their inactivity seems to be due to the difference in side chains orientations of Tyr2, Phe3, and Arg8, important for interactions with the receptors. Again, the potent antidiuretic activity of DAVP can be explained by CD data suggesting differences in mutual arrangement of the aromatic side chains of Tyr2 and Phe3 in this peptide in liposomes rather than of native AVP. In the presence of liposomes, the smallest conformational changes of the peptides are noticed with DPPC and the largest with DPPG liposomes. This suggests that electrostatic interactions are crucial for the peptide–membrane interactions. We obtained similar, probably active, conformations of the antidiuretic agonists in the mixed DPC/SDS micelles (5:1) and in the mixed DPPC/DPPG (7:3) liposomes. Thus it can be speculated that the anionic–zwitterionic liposomes as well as the anionic–zwitterionic micelles, mimicking the eukaryotic cell membrane environment, partially restrict conformational freedom of the peptides and probably induce conformations resembling those of biologically relevant ones.
Collapse
Affiliation(s)
- Emilia A Lubecka
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308, Gdańsk, Poland.
| | - Emilia Sikorska
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308, Gdańsk, Poland
| | - Dariusz Sobolewski
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308, Gdańsk, Poland
| | - Adam Prahl
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308, Gdańsk, Poland
| | - Jiřina Slaninová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10, Prague, Czech Republic
| | - Jerzy Ciarkowski
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308, Gdańsk, Poland
| |
Collapse
|
8
|
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.
Collapse
Affiliation(s)
- Qingxin Li
- Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | | | | | | | | |
Collapse
|
9
|
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.
Collapse
|
10
|
Kim YM, Li Q, Ng HQ, Yoon HS, Kang C. ¹H, ¹³C and ¹⁵N chemical shift assignments for the N-terminal PAS domain of the KCNH channel from zebrafish. BIOMOLECULAR NMR ASSIGNMENTS 2014; 8:165-168. [PMID: 23595857 DOI: 10.1007/s12104-013-9475-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 04/09/2013] [Indexed: 06/02/2023]
Abstract
The KCNH channels are voltage-gated potassium channels that play important roles in heart and nerve cells. The N-terminal region of the KCNH channel contains a Per-Arnt-Sim (PAS) domain which is important for the channel gating through interaction with other regions of the channel. To study the solution structure of the N-terminal PAS domain of the KCNH channel from Zebrafish (zNTD), we over-expressed and purified zNTD. We report the resonance assignments for zNTD. The data will allow us to perform structural studies for this domain, which will provide insight into its structural basis for the molecular interaction with other regions of the KCNH channel.
Collapse
Affiliation(s)
- Young Mee Kim
- Experimental Therapeutics Centre, Agency for Science, Technology and Research, 31 Biopolis Way Nanos, #03-01, Singapore, 138669, Singapore
| | | | | | | | | |
Collapse
|
11
|
Ng HQ, Kim YM, Huang Q, Gayen S, Yildiz AA, Yoon HS, Sinner EK, Kang C. Purification and structural characterization of the voltage-sensor domain of the hERG potassium channel. Protein Expr Purif 2012; 86:98-104. [PMID: 23041462 DOI: 10.1016/j.pep.2012.09.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 09/13/2012] [Accepted: 09/14/2012] [Indexed: 12/15/2022]
Abstract
The hERG (human ether à go-go related gene) potassium channel is a voltage-gated potassium channel playing important roles in the heart by controlling the rapid delayed rectifier potassium current. The hERG protein contains a voltage-sensor domain (VSD) that is important for sensing voltage changes across the membrane. Mutations in this domain contribute to serious heart diseases. To study the structure of the VSD, it was over-expressed in Escherichia coli and purified into detergent micelles. Lyso-myristoyl phosphatidylglycerol (LMPG) was shown to be a suitable detergent for VSD purification and folding. Secondary structural analysis using circular dichroism (CD) spectroscopy indicated that the purified VSD in LMPG micelles adopted α-helical structures. Purified VSD in LMPG micelles produced dispersed cross-peaks in a (15)N-HSQC spectrum. Backbone resonance assignments for residues from transmembrane segments S3 and S4 of VSD also confirmed the presence of α-helical structures in this domain. Our results demonstrated that structure of VSD can be investigated using NMR spectroscopy.
Collapse
Affiliation(s)
- Hui Qi Ng
- Experimental Therapeutics Centre, Singapore
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Ng CA, Torres AM, Pagès G, Kuchel PW, Vandenberg JI. Insights into hERG K+ channel structure and function from NMR studies. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2012; 42:71-9. [DOI: 10.1007/s00249-012-0808-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 03/07/2012] [Accepted: 03/13/2012] [Indexed: 01/09/2023]
|
13
|
Warschawski DE, Arnold AA, Beaugrand M, Gravel A, Chartrand É, Marcotte I. Choosing membrane mimetics for NMR structural studies of transmembrane proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1957-74. [DOI: 10.1016/j.bbamem.2011.03.016] [Citation(s) in RCA: 239] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 03/28/2011] [Accepted: 03/29/2011] [Indexed: 12/11/2022]
|
14
|
Fougere RR, Es-Salah-Lamoureux Z, Rezazadeh S, Eldstrom J, Fedida D. Functional characterization of the LQT2-causing mutation R582C and the associated voltage-dependent fluorescence signal. Heart Rhythm 2011; 8:1273-80. [DOI: 10.1016/j.hrthm.2011.02.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Accepted: 02/24/2011] [Indexed: 11/16/2022]
|