Rate-limiting guanosine 5′-triphosphate hydrolysis during nucleotide turnover by FtsZ, a prokaryotic tubulin homologue involved in bacterial cell division
Rate-limiting guanosine 5′-triphosphate hydrolysis during nucleotide turnover by FtsZ, a prokaryotic tubulin homologue involved in bacterial cell division
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DOI：
10.1021/bi035465r
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发表时间：
2004-01-13
期刊：
影响因子：
2.9
通讯作者：
Mitchison, TJ
中科院分区：
文献类型：
--
作者：
Romberg, L;Mitchison, TJ
FtsZ 是一种原核微管蛋白同源物，在细胞分裂过程中聚合成动态环。 GTP 结合和水解为 FtsZ 动力学提供能量。然而，水解在聚合物组装和周转中的确切作用尚不清楚，这限制了我们对 FtsZ 在细胞中如何发挥作用的理解。在这里，我们使用几种互补的方法研究 FtsZ 聚合循环期间的 GTP 水解，避免了先前研究的技术问题。我们发现在稳定状态下，大约 80% 的 FtsZ 聚合物亚基与 GTP 结合。此外，我们使用前稳态、单周转测定来直接测量水解速率。水解被发现以类似于 8/min 的速度发生，并且是 GTP 周转中的限速步骤；随后磷酸盐迅速释放。这些结果澄清了文献中先前相互矛盾的结果，并表明纯 FtsZ 聚合物与微管不同，可能无法经历动态不稳定或在聚合物中储存能量以产生力。
FtsZ is a prokaryotic tubulin homologue that polymerizes into a dynamic ring during cell division. GTP binding and hydrolysis provide the energy for FtsZ dynamics. However, the precise role of hydrolysis in polymer assembly and turnover is not understood, limiting our understanding of how FtsZ functions in the cell. Here we investigate GTP hydrolysis during the FtsZ polymerization cycle using several complementary approaches that avoid technical caveats of previous studies. We find that at steady state similar to80% of FtsZ polymer subunits are bound to GTP. In addition, we use pre-steady-state, single turnover assays to directly measure the rate of hydrolysis. Hydrolysis was found to occur at similar to8/min and to be a rate-limiting step in GTP turnover; phosphate release rapidly followed. These results clarify previously conflicting results in the literature and suggest that pure FtsZ polymers, unlike microtubules, may not be able to undergo dynamic instability or to store energy in the polymer for force production.