EhaA is a novel autotransporter protein of enterohemorrhagic Escherichia coli O157:H7 that contributes to adhesion and biofilm formation.
EhaA is a novel autotransporter protein of enterohemorrhagic Escherichia coli O157:H7 that contributes to adhesion and biofilm formation.
复制标题
DOI：
10.1111/j.1462-2920.2007.01479.x
复制
发表时间：
2008-03
影响因子：
5.1
通讯作者：
T. Wells;O. Sherlock;Lucy Rivas;A. Mahajan;S. Beatson;M. Torpdahl;R. Webb;L. Allsopp;K. Gobius;D. Gally;M. Schembri
中科院分区：
文献类型：
--
作者：
T. Wells;O. Sherlock;Lucy Rivas;A. Mahajan;S. Beatson;M. Torpdahl;R. Webb;L. Allsopp;K. Gobius;D. Gally;M. Schembri
自转运蛋白（AT）已被确定在许多革兰氏阴性病原体和独特的，因为它们的一级序列是足以指导其运输通过细菌膜系统。在表征时，它们一致地与毒力相关。使用保守的AT基序作为搜索工具，在肠出血性大肠杆菌O 157：H7 EDL 933基因组中鉴定出四种假定的AT蛋白。通过PCR扩增、克隆和表达这些蛋白（z 0402/ehaA、z 0469/ehaB、z3487/ehaC和z3948/ehaD）的基因。coli K-12 MG 1655流感背景。初步表征显示，ehaA，ehaB和ehaD编码的蛋白质与增加生物膜形成。其中一个基因（ehaA）位于大肠杆菌的基因组岛上。coli O 157：H7菌株EDL 933和Sakai。EhaA在E. coliK-12的表达结果表明，该蛋白定位于细胞表面，可形成大的细胞聚集体，促进生物膜的形成，并介导与牛直肠末端原代上皮细胞的粘附。在E. coliEDL 933进行RT-PCR。EhaA特异性抗体显示EhaA蛋白在24/50株产滋贺毒素的大肠杆菌中表达。大肠杆菌（STEC）菌株的各种血清型，包括O 157：H7。然而，从E. coli EDL 933和血清型O 111：H（-）的STEC菌株对生物膜生长无影响。我们的研究结果表明EhaA可能有助于E. coli O 157：H7和可能的其他STEC血清型。
Autotransporter (AT) proteins have been identified in many Gram-negative pathogens and are unique in that their primary sequence is sufficient to direct their transport across the bacterial membrane system. Where characterized they are uniformly associated with virulence. Using conserved AT motifs as a search tool, four putative AT proteins were identified in the Enterohemorrhagic Escherichia coli O157:H7 EDL933 genome. The genes encoding these proteins (z0402/ehaA, z0469/ehaB, z3487/ehaC and z3948/ehaD) were PCR amplified, cloned and expressed in an E. coli K-12 MG1655flu background. Preliminary characterization revealed that ehaA, ehaB and ehaD encode proteins associated with increased biofilm formation. One of these genes (ehaA) resides on a genomic island in E. coli O157:H7 strains EDL933 and Sakai. Over-expression of EhaA in E. coli K-12 demonstrated it is located at the cell surface and resulted in the formation of large cell aggregates, promoted significant biofilm formation and mediated adhesion to primary epithelial cells of the bovine terminal rectum. The expression of ehaA was demonstrated in E. coli EDL933 by RT-PCR. An EhaA-specific antibody revealed the EhaA protein was expressed in 24/50 generic Shiga toxin-producing E. coli (STEC) strains of various serotypes including O157:H7. However, the deletion of ehaA from E. coli EDL933 and a STEC strain from serotype O111:H(-) did not affect biofilm growth. Our results suggest that EhaA may contribute to adhesion, colonization and biofilm formation by E. coli O157:H7 and possibly other STEC serotypes.