Microbial K+ channels.
Microbial K+ channels.
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DOI：
10.1085/jgp.200509261
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发表时间：
2005-06
期刊：
影响因子：
--
通讯作者：
Saimi Y
中科院分区：
文献类型：
--
作者：
Loukin SH;Kuo MM;Zhou XL;Haynes WJ;Kung C;Saimi Y
对现有基因组的调查表明，在大多数自由生活的细菌、古细菌和原生生物中都发现了K+通道，这表明在这三个主要生命领域分化之前的早期进化。虽然是从原始K+通道垂直下降的，但最近K+通道基因的横向转移也一定发生过。观察到跨膜或细胞质结构域的基序变化，S4特征，门控机制，甚至假定的K+过滤序列。有限的实验和对游离与寄生细菌的序列调查表明，在一般情况下，K+通道不是生存所必需的。大肠杆菌中唯一的K+通道可能不是用于K+摄取，而是用于体内静息电位调节。原生生物（真核单细胞）差异很大；裂变酵母没有可识别的K+通道基因，而草履虫有298个，大约是人类基因组数量的三倍。JGP读者熟悉使用选择的微生物通道在原子分辨率上解析结构的满足感。然而，樱桃采摘并不能提供树的视图，更不用说在公共领域搜索到的270种原核生物（细菌和古细菌），15种真菌和25种原生生物的“完整”基因组的扩展森林了。从分子标记的客观分析，如小亚基核糖体rna （ssrRNAs）可以看出，植物和动物只构成生命多样性的很小一部分。这些ssrRNAs是普遍存在的，它们的核苷酸序列相似性程度被用来衡量亲缘关系（图1）。以下是从基因组调查和有限实验中收集到的微生物K+通道的综述。
A survey of the currently available genomes shows that K+ channels are found in most free-living bacteria, archaea, and protists, indicating early evolution before the divergences of the three major domains of life. Though vertically descended from the primordial K+ channels, more recent lateral transfers of K+ channel genes must also have occurred. Variations in the motifs of transmembrane or cytoplasmic domains, S4 features, gating mechanism, and even the putative K+ filter sequence are observed. Limited experimentation and sequence survey of free-ling versus parasitic bacteria show that K+ channels are not essential for survival in ordinary circumstances. The lone K+ channel in Escherichia coli is probably not for K+ uptake but for resting-potential regulation in vivo. Protists (eukaryotic unicells) vary greatly; the fission yeast has no recognizable K+ channel gene while paramecium has 298, some three times the number found in the human genome. JGP readers are familiar with the satisfaction of using choice microbial channels to resolve structures at atomic resolutions. However, cherry picking does not provide a view of the tree, let alone the expanding forest of “completed” genomes of 270 prokaryotes (bacteria and archaea), 15 fungi, and 25 protists searchable in the public domain at this writing. Plants and animals constitute only a very small slice of life’s diversity, as evident from objective analyses of molecular markers, such as the small subunit ribosomal RNAs (ssrRNAs). These ssrRNAs are universal and the degree of their nucleotide sequence similarity is used to gauge relatedness (Fig. 1). The following is a summary on microbial K+ channels, as gleaned from genome survey and limited experimentations.
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影响因子：
56.9
作者：
Doyle, DA;Cabral, JM;MacKinnon, R
通讯作者：
MacKinnon, R
影响因子：
--
作者：
Haynes, WJ;Ling, KY;Kung, C
通讯作者：
Kung, C
影响因子：
56.9
作者：
Cuello, LG;Cortes, DM;Perozo, E
通讯作者：
Perozo, E
DOI：
10.1074/jbc.c400417200
发表时间：
2004-11-05
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Enkvetchakul D;Bhattacharyya J;Jeliazkova I;Groesbeck DK;Cukras CA;Nichols CG
通讯作者：
Nichols CG
影响因子：
2.9
作者：
Irizarry, SN;Kutluay, E;Heginbotham, L
通讯作者：
Heginbotham, L