Pumping ions
Pumping ions
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DOI：
10.1111/j.1440-1681.2011.05590.x
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发表时间：
2011-11-01
影响因子：
2.9
通讯作者：
Fan, Xiaochen
中科院分区：
文献类型：
--
作者：
Clarke, Ronald J.;Fan, Xiaochen
从作者的角度对离子泵浦领域进行了简要的回顾。这段时间跨越了19世纪50年代卡尔·施密特发现的跨越动物细胞膜的Na+和K+浓度梯度，到1957年Skou分离出Na+/K+-ATPase(因此他获得了1997年诺贝尔化学奖)，作者所在课题组对该酶在Na+/K+-ATPase反应循环中的变构作用机制，以及该酶的原构体与二原构体状态对其动力学的影响等问题的解决作出了贡献。结果表明，Na+/K+-ATPase只有一个ATP结合位点，在Na+/K+-ATPase中，长期存在的争议可以通过ATP诱导的(α-β)(2)直接异构体解离成单独的α-β原构体来解决。动力学数据表明，当(α-β)(2)直接异构体中只有一个α-亚基与ATP结合时，(α-β)(2)直接异构体中两个α-β原构体之间的蛋白质-蛋白质相互作用导致酶的周转率低得多(即减速)。异丙基异构体中的非活性α-β原构体可被认为对活性原构体造成拖累。
This is a concise review of the field of ion pumping from the perspective of the authors.The period covered spans the discovery of Na+ and K+ concentration gradients across animal cell membranes by Carl Schmidt in the 1850s, through the isolation of the Na+/K+-ATPase by Skou in 1957 (for which he was awarded the 1997 Nobel Prize in Chemistry), to the publication of the first crystal structure of the enzyme in 2007 and beyond.Contributions of the authors' research group to the resolution of the questions of the mechanism of the allosteric role of ATP within the Na+/K+-ATPase reaction cycle and how protomeric versus diprotomeric states of the enzyme influence its kinetics are discussed within the context of the research field.The results obtained indicate that the Na+/K+-ATPase has a single ATP binding site, which can be catalytic or allosteric in different parts of the enzyme's reaction cycle.The long-running controversy over whether P-type ATPases function as protomers or diprotomers can be resolved in the case of the Na+/K+-ATPase by an ATP-induced dissociation of (alpha beta)(2) diprotomers into separate alpha beta protomers.Kinetic data suggest that protein-protein interactions between the two alpha beta protomers within an (alpha beta)(2) diprotomer result in a much lower enzymatic turnover (i.e. a lower gear) when only one of the alpha-subunits of the diprotomer has bound ATP. The inactive alpha beta protomer within the diprotomer can be thought of as causing a drag on the active protomer.