Chlamydophila pneumoniae HfIX belongs to an uncharacterized family of conserved GTPases and associates with the Escherichia coli 50S large ribosomal subunit
Chlamydophila pneumoniae HfIX belongs to an uncharacterized family of conserved GTPases and associates with the Escherichia coli 50S large ribosomal subunit
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DOI：
10.1099/mic.0.2008/022137-0
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发表时间：
2008-11-01
期刊：
影响因子：
2.8
通讯作者：
Vaughan, Lloyd
中科院分区：
文献类型：
--
作者：
Polkinghorne, Adam;Ziegler, Urs;Vaughan, Lloyd
磷酸结合环鸟苷三磷酸酶(GTP酶)的HFIX亚家族成员在细菌界中广泛分布，但实际上仍未确定其特征。为了了解衣原体生长和发育的调节机制，专属细胞内和发育复杂的细菌，我们已经开始研究衣原体GTP酶；我们在这里报告似乎是第一次使用肺炎衣原体的预测同源物对HfIX家族GTP酶进行分析。与该GTPase家族成员的系统发育预测一致，纯化的重组CP。肺炎杆菌HfIX对鸟嘌呤核苷酸是特异的，当与[Gamma-P-32]GTP孵育时，表现出缓慢的固有GTPase活性。使用HfIX特异性的单抗，可以通过Western blotting和高分辨率共聚焦显微镜在CP的营养生长周期中检测到HfIX。肺炎，并在早期的时间点，似乎部分定位于膜。CP的异位表达。肺炎克雷伯菌HfIX与大肠杆菌50S大核糖体亚基共沉淀。这项工作的结果为GTP酶的作用提供了一些有趣的可能性，这些GTP酶属于这个以前未被描述的细菌GTP酶家族。核糖体结合是其他重要保守的GTP酶家族共有的特征，需要更详细的研究来描述HfIX在细菌核糖体功能中的作用。
Predicted members of the HfIX subfamily of phosphate-binding-loop guanosine triphosphatases (GTPases) are widely distributed in the bacterial kingdom but remain virtually uncharacterized. In an attempt to understand mechanisms used for regulation of growth and development in the chlamydiae, obligate intracellular and developmentally complex bacteria, we have begun investigations into chlamydial GTPases; we report here what appears to be the first analysis of a HfIX family GTPase using a predicted homologue from Chlamydophila pneumoniae. In agreement with phylogenetic predictions for members of this GTPase family, purified recombinant Cp. pneumoniae HfIX was specific for guanine nucleotides and exhibited a slow intrinsic GTPase activity when incubated with [gamma-P-32]GTP. Using HfIX-specific monoclonal antibodies, HfIX could be detected by Western blotting and high-resolution confocal microscopy throughout the vegetative growth cycle of Cp. pneumoniae and, at early time points, appeared to partly localize to the membrane. Ectopic expression of Cp. pneumoniae HfIX in Escherichia coli revealed co-sedimentation of HfIX with the E coli 50S large ribosomal subunit. The results of this work open up some intriguing possibilities for the role of GTPases belonging to this previously uncharacterized family of bacterial GTPases. Ribosome association is a feature shared by other important conserved GTPase families and more detailed investigations will be required to delineate the role of HfIX in bacterial ribosome function.