ESCHERICHIA-COLI MUTANT DEFECTIVE IN SINGLE-STRAND BINDING-PROTEIN IS DEFECTIVE IN DNA-REPLICATION
ESCHERICHIA-COLI MUTANT DEFECTIVE IN SINGLE-STRAND BINDING-PROTEIN IS DEFECTIVE IN DNA-REPLICATION
复制标题
DOI：
10.1073/pnas.76.4.1702
复制
发表时间：
1979-01-01
影响因子：
11.1
通讯作者：
KORNBERG, A
中科院分区：
文献类型：
--
作者：
MEYER, RR;GLASSBERG, J;KORNBERG, A
大肠杆菌突变体对体内和体外 DNA 合成温度敏感，其单链结合蛋白（SSB；DNA 结合蛋白）有缺陷。噬菌体 G4 单链向双链体形式的转化在突变体的粗酶级分中是有缺陷的，并且由纯野生型 SSB 补充。突变体提取物的放射免疫测定显示与抗 SSB 抗体发生交叉反应的物质水平正常。纯化至突变体均质的 SSB 在 30°C 的重构 G4 复制测定中具有活性，但比活性较低。 C，但在 42 度时几乎不活跃。 C. 突变蛋白与野生型蛋白一样，可以在 100°C 的加热下存活。 C.因此，突变体SSB在结构上是耐热的，但在体外和体内功能上是热敏感的。体内和体外缺陷都与噬菌体 P1 的转导密切相关。结合蛋白的突变被称为 ssb-1，位于大肠杆菌遗传图谱上的 90 至 91 分钟之间。
An E. coli mutant, temperature-sensitive for DNA synthesis in vivo and in vitro, is defective in single-strand binding protein (SSB; DNA-binding protein). Conversion of phage G4 single strands to the duplex form is defective in crude enzyme fractions of the mutant and is complemented by pure wild-type SSB. Radioimmunoassays of mutant extracts show normal levels of material crossreacting with anti-SSB antibody. SSB purified to homogeneity for the mutant is active, with lower specific activity, in the reconstituted G4 replication assay at 30.degree. C, but virtually inactive at 42.degree. C. The mutant protein, like the wild-type protein, survives heating at 100.degree. C. Thus, mutant SSB is structurally heat-resistant but is functionally thermosensitive in vitro and in vivo. Both the in vivo and in vitro defects are tightly linked in transductions by phage P1. The mutation in the binding protein, designated ssb-1, is located between 90 and 91 min on the E. coli genetic map.