Karyagina A S, Lunin V G, Nikolskaya I I
Institute of Medical Enzymology, U.S.S.R. Academy of Medical Sciences, Moscow.
Gene. 1990 Mar 1;87(1):113-8. doi: 10.1016/0378-1119(90)90501-h.
The genes encoding SsoI and SsoII restriction endonuclease (ENase) and methyltransferase (MTase) are located on the small plasmids P6 and P4, respectively, of Shigella sonnei strain 47. Functions provided by plasmids P5, P7 and P9, which include colicinogenicity and immunity to colicin E1, resistance to streptomycin (Sm), and conjugative DNA transfer, respectively, have also been identified. The genes of the SsoII restriction-modification (R-M) system have been cloned into Escherichia coli expressing the 35-kDa (ENase) and 43-kDa (MTase) products. A restriction map of the P4 plasmid DNA was determined, and the approximate location of the genes encoding SsoII ENase and MTase (ssoIIR and ssoIIM) on that have been established. SsoI is an isoschisomer of EcoRI and SsoII cleaves the 5'-/CCNGG/recognition sequence producing 5'-protruding 5-nt long cohesive ends.
编码SsoI和SsoII限制性内切酶（ENase）及甲基转移酶（MTase）的基因分别位于宋内志贺氏菌47株的小质粒P6和P4上。也已鉴定出质粒P5、P7和P9所赋予的功能，它们分别包括产大肠杆菌素及对大肠杆菌素E1的免疫性、对链霉素（Sm）的抗性以及接合性DNA转移。SsoII限制修饰（R-M）系统的基因已被克隆到表达35 kDa（ENase）和43 kDa（MTase）产物的大肠杆菌中。测定了P4质粒DNA的限制性图谱，并确定了编码SsoII ENase和MTase（ssoIIR和ssoIIM）的基因在其上的大致位置。SsoI是EcoRI的同裂酶，SsoII切割5'-/CCNGG/识别序列，产生5'-突出的5个核苷酸长的粘性末端。
