Titball R W, Hunter S E, Martin K L, Morris B C, Shuttleworth A D, Rubidge T, Anderson D W, Kelly D C
Chemical Defence Establishment, Salisbury, Wiltshire, United Kingdom.
Infect Immun. 1989 Feb;57(2):367-76. doi: 10.1128/iai.57.2.367-376.1989.
A fragment of DNA containing the gene coding for the phospholipase C (alpha-toxin) of Clostridium perfringens was cloned into Escherichia coli. The cloned DNA appeared to code only for the alpha-toxin and contained both the coding region and its associated gene promoter. The nucleotide sequence of the cloned DNA was determined, and an open reading frame was identified which encoded a protein with a molecular weight of 42,528. By comparison of the gene sequence with the N-terminal amino acid sequence of the protein, a 28-amino-acid signal sequence was identified. The gene promoter showed considerable homology with the E. coli sigma 55 consensus promoter sequences, and this may explain why the gene was expressed by E. coli. The cloned gene product appeared to be virtually identical to the native protein. A 77-amino-acid stretch that was close to the N terminus of the alpha-toxin showed considerable homology with similarly located regions of the Bacillus cereus phosphatidylcholine, preferring phospholipase C and weaker homology with the phospholipase C from Pseudomonas aeruginosa.
将含有产气荚膜梭菌磷脂酶C（α毒素）编码基因的一段DNA片段克隆到大肠杆菌中。克隆的DNA似乎仅编码α毒素，并且包含编码区及其相关的基因启动子。确定了克隆DNA的核苷酸序列，并鉴定出一个开放阅读框，其编码一种分子量为42,528的蛋白质。通过将基因序列与该蛋白质的N端氨基酸序列进行比较，鉴定出一个28个氨基酸的信号序列。该基因启动子与大肠杆菌σ55共有启动子序列具有相当高的同源性，这可能解释了该基因在大肠杆菌中表达的原因。克隆的基因产物似乎与天然蛋白质几乎相同。靠近α毒素N端的一段77个氨基酸的序列与蜡样芽孢杆菌磷脂酰胆碱偏好性磷脂酶C的类似定位区域具有相当高的同源性，与铜绿假单胞菌的磷脂酶C的同源性较弱。
