Paton A W, Beutin L, Paton J C
Department of Microbiology, Women's and Children's Hospital, North Adelaide, Australia.
Gene. 1995 Feb 3;153(1):71-4. doi: 10.1016/0378-1119(94)00777-p.
PCR was used to amplify approx. 1470-bp segments of DNA containing complete Shiga-like toxin type I (sltI) operons from Escherichia coli strains belonging to serotypes O48:H21, O111:H- and OX3:H8. These fragments were cloned and DNA sequence analysis identified several variations, as compared with published sltI sequences. All three sltI genes analysed were more closely related to Shiga toxin-encoding genes (sht) of Shigella dysenteriae type 1, than to previously published E. coli phage-encoded sltI genes. The greatest deviation in deduced amino acid (aa) sequence was observed in the SltI protein from the OX3:H8 strain, which differed from the phage 933J-encoded SltI by 9 aa in the A subunit and 3 aa in the B subunit.
采用聚合酶链反应（PCR）从血清型为O48:H21、O111:H-和OX3:H8的大肠杆菌菌株中扩增出约1470碱基对的DNA片段，这些片段包含完整的I型志贺样毒素（sltI）操纵子。将这些片段进行克隆，并通过DNA序列分析确定了与已发表的sltI序列相比的几个变异。与先前发表的大肠杆菌噬菌体编码的sltI基因相比，所分析的所有三个sltI基因与痢疾志贺菌1型的志贺毒素编码基因（sht）的关系更为密切。在OX3:H8菌株的SltI蛋白中观察到推导氨基酸（aa）序列的最大偏差，其A亚基与噬菌体933J编码的SltI相差9个氨基酸，B亚基相差3个氨基酸。
