Structural Change in FtsZ Induced by Intermolecular Interactions between Bound GTP and the T7 Loop
Structural Change in FtsZ Induced by Intermolecular Interactions between Bound GTP and the T7 Loop
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DOI：
10.1074/jbc.m113.514901
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发表时间：
2014-02-07
影响因子：
4.8
通讯作者：
Tanaka, Isao
中科院分区：
文献类型：
--
作者：
Matsui, Takashi;Han, Xuerong;Tanaka, Isao
背景：SaFtsZ以组装的直原丝的形式结晶，相对于单体FtsZ，其子域具有大规模的滑动/旋转。结果：T7环的突变体也以原丝的形式结晶，但亚结构域的运动变化较大。结论：子结构域的移动与T7环的分子间相互作用密切相关。意义：亚结构域运动产生GTPase活性原丝，诱导直线向弯曲构象变化。FtsZ是微管蛋白的原核同源物，是细菌细胞分裂的关键分子。结合GTP的FtsZ聚合成微管样原丝。聚合时，一个亚基的T7环插入到第二个亚基的核苷酸结合口袋中，导致GTP水解。因此，T7环对于微管蛋白/FtsZ家族的聚合和水解都很重要。虽然x射线晶体学显示了微管蛋白的直线和弯曲构象，但FtsZ只知道弯曲结构。然而，最近，来自金黄色葡萄球菌的FtsZ已被证明具有与标准FtsZ结构非常不同的构象。本研究通过诱变实验研究了金黄色葡萄球菌FtsZ的结构；研究了T7环氨基酸变化对其结构和GTPase活性的影响。这些分析表明，FtsZ通过结合核苷酸和T7环残基之间的分子间相互作用，在N-和c -亚结构域之间移动，从而改变了其适合聚合和GTP水解的构象。
Background:SaFtsZ crystallizes in the form of assembled straight protofilaments, with large scale sliding/rotation of its subdomains relative to monomeric FtsZ. Results: Mutants of the T7 loop also crystallized as protofilaments, but the subdomain movement was quite variable. Conclusion: Subdomain movement is strongly correlated with intermolecular interactions via the T7 loop. Significance: Subdomain movement generates GTPase active protofilament and induces the straight to curved conformational change.FtsZ is a prokaryotic homolog of tubulin and is a key molecule in bacterial cell division. FtsZ with bound GTP polymerizes into tubulin-like protofilaments. Upon polymerization, the T7 loop of one subunit is inserted into the nucleotide-binding pocket of the second subunit, which results in GTP hydrolysis. Thus, the T7 loop is important for both polymerization and hydrolysis in the tubulin/FtsZ family. Although x-ray crystallography revealed both straight and curved conformations of tubulin, only a curved structure was known for FtsZ. Recently, however, FtsZ from Staphylococcus aureus has been shown to have a very different conformation from the canonical FtsZ structure. The present study was performed to investigate the structure of FtsZ from Staphylococcus aureus by mutagenesis experiments; the effects of amino acid changes in the T7 loop on the structure as well as on GTPase activity were studied. These analyses indicated that FtsZ changes its conformation suitable for polymerization and GTP hydrolysis by movement between N- and C-subdomains via intermolecular interactions between bound nucleotide and residues in the T7 loop.