禽大肠杆菌外膜蛋白基因C(ompC)的序列分析

根据 Gen Bank中人源大肠杆菌 K- 12外膜蛋白基因 C(omp C)的核苷酸序列设计引物 ,应用 PCR方法从禽大肠杆菌 O2 、O78株及它们的融合双价弱毒菌株 O2 ,78(Norr Chlr)中分别扩增得到 omp C基因 ,序列测定及分析比较发现 ,3个菌株的 om p C基因均由 170 2 nt组成 ,核苷酸序列完全相同 ,只有 1个大的开放性阅读框 (ORF) ,长 10 92 bp,编码由 36 3个氨基酸组成的前 Om p C蛋白 ,前 2 1个氨基酸残基组成信号肽 ,成熟的 Omp C蛋白由 342个氨基酸残基组成 ,Mr为 4 0 0 0 0。其氨基酸序列也完全相同。从基因水平上证明了禽大肠杆菌 O2 、O78株及融合双价弱毒菌株 O2 ,78(NorrChlr)存在相同的外膜蛋白 C抗原 ,从而为进一步研究 Omp C蛋白的免疫原性奠定了基础

Sequence Analysis of the Outer Membrane Protein Gene ompC of Avian Escherichia coli

A pair of primers were designated based on the DNA sequence of the ompC gene of Escherichia coli K-12 in GenBank.With the special primers,ompC genes of E.coli O_(2),O_(78) and their fusion bivalent attenuated strain O_(2,78) were amplified by PCR.After sequenced,all of the three ompC genes contained (1 702) bp.Starting at nucleotide 491 and ending at nucleotide (1 582),an open reading frame(ORF) of (1 092) nt encodes the pro-OmpC protein consisting of 363 amino acid residuces.Hydrophobicity analysis suggested that the preceeding 21 amino acid constitute a typical signal sequence,suggesting that the mature form of OmpC protein is 342 amino acid long with the molecular weight (40 000).Analysis the nucleotide and amino acid sequence of the three ompC genes of avian Escherichia coli showed that the homology both were 100%.These results indicated that O_(2) and O_(78) have same outer membrane protein C antigen.