Bobrov Alexander G, Kirillina Olga, Perry Robert D
Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, KY 40536-0298, USA.
FEMS Microbiol Lett. 2005 Jun 15;247(2):123-30. doi: 10.1016/j.femsle.2005.04.036.
In Yersinia pestis, biofilm formation is stimulated by HmsT, a GGDEF-domain containing protein that synthesizes cyclic-di-GMP (c-di-GMP), and inhibited by HmsP, an EAL-domain protein. Only the EAL-domain portion of HmsP is required to inhibit biofilm formation. The EAL domain of HmsP was purified as a 6XHis-tag fusion protein and demonstrated to have phosphodiesterase activity using bis(p-nitrophenyl) phosphate (bis-pNPP) as a substrate. This enzymatic activity was strictly manganese dependent. A critical residue (E506) of HmsP within the EAL domain, that is required for inhibition of biofilm formation, is also essential for this phosphodiesterase activity. While the proposed function of EAL-domain proteins is to linearize c-di-GMP, this is a direct demonstration of the required phosphodiesterase activity of a purified EAL-domain protein.
在鼠疫耶尔森菌中，生物膜形成受HmsT刺激，HmsT是一种含有GGDEF结构域的蛋白质，可合成环二鸟苷酸（c-di-GMP），而受HmsP抑制，HmsP是一种含EAL结构域的蛋白质。抑制生物膜形成仅需HmsP的EAL结构域部分。HmsP的EAL结构域作为6XHis标签融合蛋白被纯化，并以磷酸双（对硝基苯基）酯（bis-pNPP）为底物证明具有磷酸二酯酶活性。这种酶活性严格依赖锰。HmsP在EAL结构域内的一个关键残基（E506），对于抑制生物膜形成是必需的，对于这种磷酸二酯酶活性也是必不可少的。虽然EAL结构域蛋白的推测功能是使c-di-GMP线性化，但这是纯化的EAL结构域蛋白所需磷酸二酯酶活性的直接证明。
