猪大肠杆菌热敏肠毒素A亚基基因的克隆及核苷酸序列分析

MOLECULAR CLONING AND NUCLEOTIDE SEQUENCE OF HEATLABILE ENTEROTOXIN SUBUNIT A GENE ORIGINATING IN E.COLI OF PIG ORIGIN

本文克隆了含猪源肠毒素大肠杆菌ＬＴＡ基因的６．７ｋｂＥｃｏＲＩ酶切片段，进行了限制酶图谱分析和核苷酸序列测定，共测定了１０９３ｂｐ的核苷酸序列，其中ＬＴＡ亚基基因编码区长７６５ｂｐ，编码２５４个氨基酸的蛋白质；计算分子量为２９６５２；氨基酸组成表明，ＬＴＡ富含带电荷的精氨酸、天冬氨酸和谷氨酸，同时酪氨酸和苯丙氨酸也异常的高。

おhe EcoRI67kb fragment containing the heatlabile enterotoxin subunit A(LTA) gene originating in E.coli of pig origin was cloned.The restriction endonuclease map and the nucleotide sequence were determined.The length of the determined nucleotide sequence was 1093 bp,in which the LTA coding sequence was 765 bp.The LTA gene encoded a 254 amino acid poly peptide with a predicted molecular weight of 29,652.The amino acid composition of LTA predicted from the DNA sequence showed LTA had a high content of charged residues;In addition,tyrosine and phenylalanine were abnormally high content in LTA.