Kushner S R
J Bacteriol. 1974 Dec;120(3):1219-22. doi: 10.1128/jb.120.3.1219-1222.1974.
The recBC nuclease (also called exonuclease V) has been partially purified from Escherichia coli K-12 strains carrying the thermosensitive recB270, recC271, and recB270 recC271 mutations. Of the multiple activities associated with the enzyme, only the adenosine 5'-triphosphate-dependent exonucleolytic hydrolysis of duplex deoxyribonucleic acid (DNA) is abnormally thermolabile. The exo- and endonucleolytic degradation of single-stranded DNA is no more thermosensitive than that catalyzed by the wild-type enzyme. These results suggest that the defects in genetic recombination, DNA repair, and the maintenance of cell viability observed in recBC mutants in vivo result primarily from the specific loss of adenosine 5'-triphosphate-dependent exonuclease active on duplex DNA.
已从携带温度敏感型recB270、recC271以及recB270 recC271突变的大肠杆菌K-12菌株中部分纯化出recBC核酸酶(也称为核酸外切酶V)。在与该酶相关的多种活性中,只有双链脱氧核糖核酸(DNA)的三磷酸腺苷依赖性核酸外切水解异常不耐热。单链DNA的核酸外切和核酸内切降解与野生型酶催化的反应相比,对热的敏感性并无差异。这些结果表明,在体内recBC突变体中观察到的遗传重组、DNA修复及细胞活力维持方面的缺陷,主要是由于双链DNA上三磷酸腺苷依赖性核酸外切酶活性的特异性丧失所致。