Ward L J, Beresford T P, Lubbers M W, Jarvis B D, Jarvis A W
Department of Microbiology and Genetics, Massey University, Palmerston North, New Zealand.
Can J Microbiol. 1993 Aug;39(8):767-74. doi: 10.1139/m93-113.
Approximately 80% of the genome of the prolate-headed lactococcal bacteriophage c2 was cloned into shuttle vectors pSA3 and pFX3 in Escherichia coli and transferred to Lactococcus lactis. A 1.67-kilobase EcoRV fragment containing the gene for the phage lysin was identified and the position and orientation of the phage lysin gene in the physical map of the phage were determined. The phage lysin was expressed in E. coli and its sequence was determined and compared with the sequences of other bacteriophage lytic genes. The sequence was similar, but not identical, to that of the related lactococcal phage m13, having a number of silent substitutions and an apparent deletion that altered the carboxy terminus of the protein. Possible alternative translation initiation codons for the lysin gene and two possible alternative mechanisms for access of the lysin enzyme to the cell wall are discussed. An open reading frame upstream of the putative lysin gene was found to be 177 base pairs longer than that reported for phage m13. A codon usage table for the lysin genes of several phages as well as for reported gene sequences from L. lactis and lactococcal bacteriophages is presented.
大约80%的长头乳球菌噬菌体c2的基因组被克隆到大肠杆菌中的穿梭载体pSA3和pFX3中，并转移至乳酸乳球菌。鉴定出一个含有噬菌体溶菌酶基因的1.67千碱基EcoRV片段，并确定了噬菌体溶菌酶基因在噬菌体物理图谱中的位置和方向。噬菌体溶菌酶在大肠杆菌中表达，测定了其序列，并与其他噬菌体裂解基因的序列进行了比较。该序列与相关乳球菌噬菌体m13的序列相似，但并不相同，存在一些沉默取代和一个明显的缺失，该缺失改变了蛋白质的羧基末端。讨论了溶菌酶基因可能的替代翻译起始密码子以及溶菌酶进入细胞壁的两种可能的替代机制。发现在假定的溶菌酶基因上游的一个开放阅读框比噬菌体m13报道的长177个碱基对。给出了几种噬菌体溶菌酶基因以及来自乳酸乳球菌和乳球菌噬菌体的已报道基因序列的密码子使用表。
