Assembly of cyclic enterobacterial common antigen in Escherichia coli K-12
Assembly of cyclic enterobacterial common antigen in Escherichia coli K-12
复制标题
DOI：
10.1128/jb.187.20.6917-6927.2005
复制
发表时间：
2005-10-01
影响因子：
3.2
通讯作者：
Rick, PD
中科院分区：
文献类型：
--
作者：
Kajimura, J;Rahman, A;Rick, PD
We describe here the purification and quantification of a water-soluble cyclic form of enterobacterial common antigen (ECA(CYC)) from Escherichia coli K-12 as well as information regarding its subcellular location and the genetic loci involved in its assembly. Structural characterization of purified ECA(CYC) molecules obtained from E. coli K-12 revealed that they uniformly contained four trisaccharide repeat units, and they were substituted with from zero to four O-acetyl groups. Cells from overnight cultures contained approximately 2 mu g ECA(CYC) per milligram (dry weight), and cell fractionation studies revealed that these molecules were localized exclusively in the periplasm. The synthesis and assembly of ECA(CYC) were found to require the wzrE and wzyE genes of the wec gene cluster. These genes encode proteins involved in the transmembrane translocation of undecaprenylpyropbosphate-linked ECA trisaccharide repeat units and the polymerization of trisaccharide repeat units, respectively. Surprisingly, synthesis of ECA(CYC) was dependent on the wzz-E gene, which is required for the modulation of the polysaccharide chain lengths of phosphoglyceride-linked ECA (ECA,,). The presence of ECA(CYC) in extracts of several other gram-negative enteric organisms was also demonstrated; however, it was not detected in cell extracts of Pseudomonas aeruginosa. These data suggest that in addition to ECA(PG), ECA(CYC) may be synthesized in many, if not all, members of the Enterobacteriaceae.
