Crystallization and preliminary X-ray diffraction analyses of several forms of the CfaB major subunit of enterotoxigenic Escherichia coli CFA/I fimbriae
Crystallization and preliminary X-ray diffraction analyses of several forms of the CfaB major subunit of enterotoxigenic Escherichia coli CFA/I fimbriae
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DOI：
10.1107/s1744309109001584
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发表时间：
2009-03-01
影响因子：
0.9
通讯作者：
Xia, Di
中科院分区：
文献类型：
--
作者：
Li, Yong-Fu;Poole, Steven;Xia, Di
产肠毒素大肠杆菌（ETEC）是全球腹泻的主要原因，通过菌毛介导的附着于小肠上皮启动致病过程。一种常见的原型ETEC菌毛，定植因子抗原I（CFA/I），由尖端定位的次要粘附亚基CfaE和茎形成的主要亚基CfaB组成，这两者都是菌毛组装所必需的。为了阐明CFA/I在原子分辨率下的结构，产生了由次要和主要亚基（CfaEB）以及主要亚基的两个（CfaBB）和三个（CfaBBB）重复的融合物组成的三种重组蛋白。CfaEB晶体衍射X射线至2.1埃分辨率，并显示空间群P2（1）的对称性。CfaBB显示出2.3埃分辨率的晶体衍射极限，并且具有空间群P2（1）2（1）2的对称性。CfaBBB在单斜空间群C2中结晶，并衍射X射线至2.3埃分辨率。这些结构是使用分子置换法确定的。
Enterotoxigenic Escherichia coli (ETEC), a major global cause of diarrhea, initiates the pathogenic process via fimbriae-mediated attachment to the small intestinal epithelium. A common prototypic ETEC fimbria, colonization factor antigen I (CFA/I), consists of a tip-localized minor adhesive subunit CfaE and the stalk-forming major subunit CfaB, both of which are necessary for fimbrial assembly. To elucidate the structure of CFA/I at atomic resolution, three recombinant proteins were generated consisting of fusions of the minor and major subunits (CfaEB) and of two (CfaBB) and three (CfaBBB) repeats of the major subunit. Crystals of CfaEB diffracted X-rays to 2.1 angstrom resolution and displayed the symmetry of space group P2(1). CfaBB exhibited a crystal diffraction limit of 2.3 angstrom resolution and had the symmetry of space group P2(1)2(1)2. CfaBBB crystallized in the monoclinic space group C2 and diffracted X-rays to 2.3 angstrom resolution. These structures were determined using the molecular-replacement method.