The complete DNA sequence and analysis of the large virulence plasmid of Escherichia coli O157:H7
The complete DNA sequence and analysis of the large virulence plasmid of Escherichia coli O157:H7
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DOI：
10.1093/nar/26.18.4196
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发表时间：
1998-09-15
影响因子：
14.9
通讯作者：
Blattner, FR
中科院分区：
文献类型：
--
作者：
Burland, V;Shao, Y;Blattner, FR
给出了肠出血性大肠杆菌O 157：H7 EDL 933株的大毒力质粒pO 157的完整DNA序列。92 kb的F-样质粒是由假定的毒力基因片段的复制和维持区的框架，与7个插入序列元件，主要位于毒力片段的边界。鉴定了100个开放阅读框（ORF），其中19个是先前测序的潜在毒力基因。42个ORF与已知蛋白质足够相似，可以指定建议的功能，22个与任何已知蛋白质没有令人信服的相似性。在新鉴定的基因中，3169个氨基酸的异常大的ORF具有与大梭菌毒素（LCT）家族和艰难梭菌的蛋白质如ToxA和B共享的推定的细胞毒素活性位点。在该基因的完整序列中，在碱基组成、密码子使用和基因组结构等方面均存在嵌合现象。从DNA组成的模式以及致病和“管家”基因片段中获得了见解。从共享质粒维持基因构建的进化树表明，即使这些基因也有异质性起源。
The complete DNA sequence of pO157, the large virulence plasmid of EHEC strain O157:H7 EDL 933, is presented. The 92 kb F-like plasmid is composed of segments of putative virulence genes in a framework of replication and maintenance regions, with seven insertion sequence elements, located mostly at the boundaries of the virulence segments. One hundred open reading frames (ORFs) were identified, of which 19 were previously sequenced potential virulence genes. Forty-two ORFs were sufficiently similar to known proteins for suggested functions to be assigned, and 22 had no convincing similarity with any known proteins. Of the newly identified genes, an unusually large ORF of 3169 amino acids has a putative cytotoxin active site shared with the large clostridial toxin (LCT) family and proteins such as ToxA and B of Clostridium difficile. A conserved motif was detected that links the large ORF and the LCT proteins with the OCH1 family of glycosyltransferases, In the complete sequence, the mosaic form can be observed at the levels of base composition, codon usage and gene organization. Insights were obtained from patterns of DNA composition as well as the pathogenic and 'housekeeping' gene segments. Evolutionary trees built from shared plasmid maintenance genes show that even these genes have heterogeneous origins.