Centre for Infectious Disease Research, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia.
Microbiology (Reading). 2010 Aug;156(Pt 8):2459-2469. doi: 10.1099/mic.0.039024-0. Epub 2010 May 6.
Autotransporter (AT) proteins are found in all Escherichia coli pathotypes and are often associated with virulence. In this study we took advantage of the large number of available E. coli genome sequences to perform an in-depth bioinformatic analysis of AT-encoding genes. Twenty-eight E. coli genome sequences were probed using an iterative approach, which revealed a total of 215 AT-encoding sequences that represented three major groups of distinct domain architecture: (i) serine protease AT proteins, (ii) trimeric AT adhesins and (iii) AIDA-I-type AT proteins. A number of subgroups were identified within each broad category, and most subgroups contained at least one characterized AT protein; however, seven subgroups contained no previously described proteins. The AIDA-I-type AT proteins represented the largest and most diverse group, with up to 16 subgroups identified from sequence-based comparisons. Nine of the AIDA-I-type AT protein subgroups contained at least one protein that possessed functional properties associated with aggregation and/or biofilm formation, suggesting a high degree of redundancy for this phenotype. The Ag43, YfaL/EhaC, EhaB/UpaC and UpaG subgroups were found in nearly all E. coli strains. Among the remaining subgroups, there was a tendency for AT proteins to be associated with individual E. coli pathotypes, suggesting that they contribute to tissue tropism or symptoms specific to different disease outcomes.
自动转运蛋白（AT）存在于所有大肠杆菌病原体中，通常与毒力有关。在这项研究中，我们利用大量可获得的大肠杆菌基因组序列，对 AT 编码基因进行了深入的生物信息学分析。我们使用迭代方法探测了 28 个大肠杆菌基因组序列，总共发现了 215 个 AT 编码序列，它们代表了三种不同结构域架构的主要群体：（i）丝氨酸蛋白酶 AT 蛋白，（ii）三聚体 AT 黏附素和（iii）AIDA-I 型 AT 蛋白。在每个广泛类别中都确定了一些亚群，并且大多数亚群都包含至少一种特征化的 AT 蛋白；然而，七个亚群不包含以前描述的蛋白质。AIDA-I 型 AT 蛋白代表最大和最多样化的群体，通过基于序列的比较确定了多达 16 个亚群。AIDA-I 型 AT 蛋白亚群中的 9 个至少包含一种具有与聚集和/或生物膜形成相关的功能特性的蛋白质，表明该表型具有高度的冗余性。Ag43、YfaL/EhaC、EhaB/UpaC 和 UpaG 亚群几乎存在于所有大肠杆菌菌株中。在其余的亚群中，AT 蛋白倾向于与单个大肠杆菌病原体相关，表明它们有助于组织趋向性或特定于不同疾病结果的症状。
