Ion channels in microbes.
Ion channels in microbes.
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DOI：
10.1007/978-94-017-0998-9_10
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发表时间：
1999
影响因子：
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通讯作者：
Y. Saimi;Boris Martinac;Robin R. Preston;Zhou Xl;Sergei Sukharev;Paul Blount;Ching Kung
中科院分区：
文献类型：
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作者：
Y. Saimi;Boris Martinac;Robin R. Preston;Zhou Xl;Sergei Sukharev;Paul Blount;Ching Kung
电生理学和离子通道的研究通常是神经生物学家的领域。然而，由于膜片钳技术应用于微生物膜，很明显，微生物具有多种离子通道活动。微生物基因组测序项目已经揭示，事实上，几乎所有被调查的微生物都具有离子通道同源物。对于这些微生物离子通道基因中的一些，已经鉴定了相应的离子通道活性，特别是来自大肠杆菌的机械敏感离子通道（MscL）、来自变铅青链霉菌的K+离子通道同源物（KscA）和来自酿酒酵母的双孔K+通道（Tok 1）。这允许更详细地检查这些离子通道的结构/功能。更值得注意的是，由于微生物离子通道比哺乳动物离子通道更容易纯化和结晶，因此已经确定了MscL和KscA的晶体结构。对于KscA，这为所有K+通道中钾离子过滤器的结构提供了很好的见解。一个经常被忽视的问题是微生物中离子通道的功能。对于MscL，随着MscS的发现，这个问题已经开始得到回答，MscS与MscL平行发挥作用，以保护细胞免受渗透胁迫。然而，KscA和Tokl以及许多其他离子通道同源物的功能尚未被发现。令人着迷的是，人类感知能力的进化是基于一种分子，这种分子甚至存在于简单的生命形式中。
Electrophysiology and the study of ion channels has generally been the province of neurobiologists. However, since the application of patch clamp techniques to microbial membranes, it is evident that microbes possess a variety of ion channel activities. Microbial genome sequencing projects have revealed that, in fact, nearly all microbes that have been surveyed possess ion channel homologues. For some of these microbial ion channel genes, the corresponding ion channel activity has been identified, notably the mechanosensitive ion channel fromEscherichia coli(MscL), the K+ion channel homologue fromStreptomyces lividans(KscA) and the dual-pore K+channel fromSaccharomyces cerevisiae(Tok1). This has allowed a more detailed examination of the structure/function of these ion channels. More remarkably, due to the greater ease of purification and crystallization of microbial ion channels than mammalian ion channels, the crystal structures of both MscL and KscA have been determined. For KscA, this has given great insights into the structure of the potassium ion filter in all K+channels. An often-neglected question concerns the function of ion channels in microbes. For MscL, this question has begun to be answered with the discovery of MscS, which functions in parallel with MscL to protect cells from osmotic stress. However, the function of KscA and Tokl and many other ion channel homologues has as yet to be discovered. It is fascinating that the evolution of human sentience is based upon a molecule that is present in even simple forms of life.