Mutations in the GTP-binding and synergy loop domains of Mycobacterium tuberculosis ftsZ compromise its function in vitro and in vivo.
Mutations in the GTP-binding and synergy loop domains of Mycobacterium tuberculosis ftsZ compromise its function in vitro and in vivo.
复制标题
结核分枝杆菌 ftsZ 的 GTP 结合域和协同环域的突变会损害其体外和体内功能。
DOI：
10.1016/j.bbrc.2005.03.239
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Madiraju,MurtyV
中科院分区：
文献类型：
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作者：
Rajagopalan,Malini;Atkinson,MarkAL;Lofton,Hava;Chauhan,Ashwini;Madiraju,MurtyV
结核分枝杆菌FtsZ（FtsZTB）与其他真细菌FtsZ蛋白不同，显示出缓慢的GTP依赖性聚合和弱的GTP水解活性[E.L.白色，L. J.罗斯，R.C. Reynolds，L.E. Seitz，G. D.摩尔，D.W. Borhani，结核分枝杆菌的缓慢聚合FtsZ，细菌学杂志。182（2000）4028-4034]。为了理解这些发现的生物学意义，我们在FtsZ的GTP结合（FtsZG 103 S）和GTP水解（FtsZD 210 G）结构域中创建了突变，并表征了突变蛋白在体外和体内的活性。我们发现FtsZG 103 Sis与GTP的结合和聚合活性有缺陷，并且表现出降低的GTP酶活性，而FtsZD 210 G蛋白精通与GTP的结合，表现出降低的聚合活性，但没有表现出任何可测量的GTP酶活性。通过荧光显微镜观察ftsZ部分二倍体菌株中的FtsZ-GFP结构显示，FtsZD 210 G擅长与Z环结构结合，而FtsZG 103 S不擅长。最后，我们表明，耻垢分枝杆菌ftsZ突变株产生相应的突变FtsZ蛋白是不可行的，这表明突变FtsZ蛋白不能作为唯一的来源FtsZ，结果明显不同于大肠杆菌的报告。总之，我们的研究结果表明，最佳的GTdR和聚合活性的FtsZ需要维持细胞分裂的分枝杆菌和相同的保守突变在不同的细菌物种具有不同的表型。
The Mycobacterium tuberculosis FtsZ (FtsZTB), unlike other eubacterial FtsZ proteins, shows slow GTP-dependent polymerization and weak GTP hydrolysis activities [E.L. White, L.J. Ross, R.C. Reynolds, L.E. Seitz, G.D. Moore, D.W. Borhani, Slow polymerization of Mycobacterium tuberculosis FtsZ, J. Bacteriol. 182 (2000) 4028–4034]. In an attempt to understand the biological significance of these findings, we created mutations in the GTP-binding (FtsZG103S) and GTP hydrolysis (FtsZD210G) domains of FtsZ and characterized the activities of the mutant proteins in vitro and in vivo. We show that FtsZG103Sis defective for binding to GTP and polymerization activities, and exhibited reduced GTPase activity whereas FtsZD210Gprotein is proficient in binding to GTP, showing reduced polymerization activity but did not show any measurable GTPase activity. Visualization of FtsZ-GFP structures in ftsZ merodiploid strains by fluorescent microscopy revealed that FtsZD210Gis proficient in associating with Z-ring structures whereas FtsZG103Sis not. Finally, we show that Mycobacterium smegmatis ftsZ mutant strains producing corresponding mutant FtsZ proteins are non-viable indicating that mutant FtsZ proteins cannot function as the sole source for FtsZ, a result distinctly different from that reported for Escherichia coli. Together, our results indicate that optimal GTPase and polymerization activities of FtsZ are required to sustain cell division in mycobacteria and that the same conserved mutations in different bacterial species have distinct phenotypes.