删除分析揭示了霍乱弧菌中必需 GTPase CgtA 的特定结构域活性的见解。

Deletion analyses reveal insights into the domain specific activities of an essential GTPase CgtA in Vibrio cholerae.

机构信息

Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia, 741246, West Bengal, India; Viral Research and Diagnostic Laboratories, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme XM, Beliaghata, P.O. Box-177, Kolkata, 700 010, West Bengal, India.

Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia, 741246, West Bengal, India.

出版信息

Arch Biochem Biophys. 2019 Apr 15;665:143-151. doi: 10.1016/j.abb.2019.03.007. Epub 2019 Mar 17.

DOI:10.1016/j.abb.2019.03.007

PMID:30894284

Abstract

CgtA is an essential bacterial GTPase protein involved in multiple cellular activities. In the presence of 50S ribosome, its GTPase activity increases significantly. Through sequential deletions of CgtA protein of Vibrio cholerae (CgtA) we found that its N terminal Obg domain is essential for ribosome binding and augmenting the ribosome mediated GTPase activity. Strategic deletions of the three glycine rich loops of Obg domain revealed that loop 1 of Obg domain is involved in anchoring the protein into the 50S, whereas, loop 2 & loop 3 are involved in conveying the effect of interaction of the Obg domain with the 50S to the GTPase domain through an interdomain linker, followed by GTP hydrolysis. On the other hand, the non-conserved C-terminal domain (CTD) is not directly involved in ribosome binding but shows negative impact on GTPase activity.

摘要

CgtA 是一种参与多种细胞活动的必需细菌 GTPase 蛋白。在 50S 核糖体存在的情况下，其 GTPase 活性显著增加。通过对霍乱弧菌（CgtA）的 CgtA 蛋白进行连续缺失，我们发现其 N 端 Obg 结构域对于核糖体结合和增强核糖体介导的 GTPase 活性是必需的。Obg 结构域的三个甘氨酸丰富环的策略性缺失表明，Obg 结构域的环 1 参与将蛋白质锚定到 50S 中，而环 2 和环 3 则通过结构域间接头将 Obg 结构域与 50S 的相互作用的效果传递到 GTPase 结构域，随后进行 GTP 水解。另一方面，非保守的 C 端结构域（CTD）不直接参与核糖体结合，但对 GTPase 活性有负面影响。