A PROKARYOTIC POTASSIUM-ION CHANNEL WITH 2 PREDICTED TRANSMEMBRANE SEGMENTS FROM STREPTOMYCES-LIVIDANS
A PROKARYOTIC POTASSIUM-ION CHANNEL WITH 2 PREDICTED TRANSMEMBRANE SEGMENTS FROM STREPTOMYCES-LIVIDANS
复制标题
DOI：
10.1002/j.1460-2075.1995.tb00201.x
复制
发表时间：
1995-11-01
期刊：
影响因子：
11.4
通讯作者：
WAGNER, R
中科院分区：
文献类型：
--
作者：
SCHREMPF, H;SCHMIDT, O;WAGNER, R
本文报道了一种迄今为止唯一的原核钾离子通道（KcsA）的鉴定、功能表达、纯化、重组和电生理特性。KcsA具有整流电流-电压关系，并显示亚电导态，最大的亚电导态为λ = 90 pS。通道被Cs+离子阻断，门控需要Mg 2+离子的存在。kcsA基因已在革兰氏阳性土壤细菌变铅青链霉菌中被鉴定。它编码一个预测的17.6 kDa的蛋白质与两个潜在的跨膜螺旋连接的一个中央域，该域与真核生物离子通道之间保守的H5片段具有高度的相似性。推导的氨基酸的多重比对表明，新的通道具有最接近的亲属关系的S5，H5和S6区域的电压门控K+通道家族，主要是由来自果蝇的Shaker蛋白质的亚家族。此外，KcsA是最遥远的真核内向整流通道与两个推定的预测跨膜段。
We report the identification, functional expression, purification, reconstitution and electrophysiological characterization of an up to now unique prokaryotic potassium ion channel (KcsA), It has a rectifying current-voltage relationship and displays subconductance states, the largest of which amounts to Lambda congruent to 90 pS. The channel is blocked by Cs+ ions and gating requires the presence of Mg2+ ions, The kcsA gene has been identified in the gram-positive soil bacterium Streptomyces lividans. It encodes a predicted 17.6 kDa protein with two potential membrane-spanning helices linked by a central domain which shares a high degree of similarity with the H5 segment conserved among eukaryotic ion channels. Multiple alignments of deduced amino acids suggest that the novel channel has the closest kinship to the S5, H5 and S6 regions of voltage-gated K+ channel families, mainly to the subfamily represented by the Shaker protein from Drosophila melanogaster. Moreover, KcsA is most distantly related to eukaryotic inwardly rectifying channels with two putative predicted transmembrane segments.