摘要
本文对国内流行的猪肠毒素源性大肠杆菌K88ac抗原的结构基因的核苷酸序列进行了测定。该基因由849对核苷酸组成,编码了283个氨基酸的蛋白亚单位及21个氨基酸的信号肽。与国外报道的K88ac序列的不同是我们发现一个碱基的点突变,导致在抗原决定簇内一个氨基酸的改变。从核苷酸序列推导出的氨基酸序列与另两种亚型进行了比较。
The nucleotide sequence of the gene encoding the K88ac adhesion antigen of porcine enterotoxigenic E. coli, the main epidemic variant in our country, has been determined. The structural gene of K88ac contains 849 nucleotides encoding a protein of 283 amino acid residues and a signal peptide of 21 amino acid residues. The only difference from others reported previously is a point mutation which results in an amino acid change at the region of potential antigenic determinant. The amino acid sequence of K88ac deduced from the nucleotide sequence is compared with another two variants K88ab and K88ad.
