Experimental Therapeutics Center, The Agency for Science, Technology and Research, 31 Biopolis Way Nanos, #03-01, Singapore 138669, Singapore.
Biochem Biophys Res Commun. 2010 Dec 3;403(1):126-32. doi: 10.1016/j.bbrc.2010.10.132. Epub 2010 Nov 3.
The human Ether-à-go-go Related Gene (hERG) potassium channel mediates the rapid delayed rectifier current (IKr) in the cardiac action potential. Mutations in the 135 amino acid residue N-terminal domain (NTD) cause channel dysfunction or mis-translocation. To study the structure of NTD, it was overexpressed and purified from Escherichia coli cells using affinity purification and gel filtration chromatography. The purified protein behaved as a monomer under purification conditions. Far- and near-UV, circular dichroism (CD) and solution nuclear magnetic resonance (NMR) studies showed that the purified protein was well-folded. The solution structure of NTD was obtained and the N-terminal residues 13-23 forming an amphipathic helix which may be important for the protein-protein or protein-membrane interactions. NMR titration experiment also demonstrated that residues from 88 to 94 in NTD are important for the molecular interaction with the peptide derived from the S4-S5 linker.
人类 Eag 相关基因（hERG）钾通道介导心脏动作电位中的快速延迟整流电流（IKr）。N 端结构域（NTD）中 135 个氨基酸残基的突变会导致通道功能障碍或错误易位。为了研究 NTD 的结构，使用亲和纯化和凝胶过滤层析从大肠杆菌细胞中过表达和纯化。在纯化条件下，纯化的蛋白质表现为单体。远紫外和近紫外、圆二色性（CD）和溶液核磁共振（NMR）研究表明，纯化的蛋白质具有良好的折叠。获得了 NTD 的溶液结构，N 端残基 13-23 形成一个两亲性螺旋，这对于蛋白质-蛋白质或蛋白质-膜相互作用可能很重要。NMR 滴定实验还表明，NTD 中 88 到 94 个残基对于与来自 S4-S5 连接子的肽的分子相互作用很重要。
