禽大肠杆菌O2、O78菌株外膜蛋白A基因扩增及序列分析

    Amplified and sequence analysis of the outer membrane protein A gene of avian Escherichia coil O2, O78

    • 摘要: 根据Genbank中大肠杆菌K-12外膜蛋白A基因的核苷酸序列设计引物,从禽大肠杆菌O为O2、O78及它们的融合株O2.78(Chl^rNor^r)中分别扩增得到外膜蛋白A基因(ompA),进行序列测定及分析发现3个菌株的ompA均由2276nt组成,核苷酸序列完全相同,只有一个大的开放性阅读框(ORF),长1041bp,编码由346个氨基酸组成的前外膜蛋白A(pro-OmpA),前21个氨基酸残基组成信号肽,成熟的OmpA由325个氨基酸残基组成,相对分子质量为37000.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和O78菌株存在相同的外膜蛋白A抗原。

       

      Abstract: A pair of primers were designed based on the DNA sequence of the outer membrane protein A gene (ompA)in Genbank. With the special primers, ompA of E.coli O_2, O_(78) and their fusion bivalent attenunated strain O_(2,78) (Chl~r Nor~r) were amplified by PCR. After sequencing , all of the three ompA were shown to contain (2 276) nt. Starting at nucleotide (1 037) and ending at nucleotide (2 077), an open reading frame(ORF) of (1 041) bp encodes the pro-OmpA protein consisting of 346 amino acid residues. Hydrophobicity analysis suggested that the preceeding 21 amino acid constitute a typical signal sequence, and that the mature form of OmpA is 325 amino acid long with a relative molecular mass of (37 000). Analysis of the nucleotide sequences of the three ompA genes of avian Escherichia coli showed that they were all identical. These results indicated that O_2 and O_(78) have the same outer membrane protein A antigen.

       

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