title: Purification and structural characterization of the voltage-sensor domain of the hERG potassium channel.
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.
authors.affiliation: Experimental Therapeutics Centre, Singapore.
authors.forename: Hui Qi
authors.initials: HQ
authors.lastname: Ng
authors.forename: Young Mee
authors.initials: YM
authors.lastname: Kim
authors.forename: Qiwei
authors.initials: Q
authors.lastname: Huang
authors.forename: Shovanlal
authors.initials: S
authors.lastname: Gayen
authors.forename: Ahu Arslan
authors.initials: AA
authors.lastname: Yildiz
authors.forename: Ho Sup
authors.initials: HS
authors.lastname: Yoon
authors.forename: Eva-Kathrin
authors.initials: EK
authors.lastname: Sinner
authors.forename: CongBao
authors.initials: C
authors.lastname: Kang
mesh_terms: D002942:Circular Dichroism; D003902:Detergents / Q000737:chemistry; D000072237:ERG1 Potassium Channel; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D051638:Ether-A-Go-Go Potassium Channels / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D010715:Phosphatidylglycerols / Q000737:chemistry; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification
chemical_list: D003902:Detergents; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C000606913:KCNH2 protein, human; D008823:Micelles; D010715:Phosphatidylglycerols; D011994:Recombinant Proteins; C552372:lysomyristoylphosphatidylglycerol