Mulder J A, Venema G
J Bacteriol. 1982 Oct;152(1):166-74. doi: 10.1128/jb.152.1.166-174.1982.
A comparison of the nucleolytic activities in competent and physiologically low-competent wild-type cultures of Bacillus subtilis in DNA-containing sodium dodecyl sulfate-polyacrylamide gels revealed the existence of three competence-associated nuclease activities with apparent molecular weights of 13,000, 15,000, and 26,000. The three activities, which were dependent on manganese or magnesium ions, were specifically present in the competent fraction of a competent culture. The competence-associated nucleolytic activities of eight transformation-defective mutant strains were assayed, resulting in the following three classes of mutants: (i) four strains which, according to this assay, were not impaired in any of the nucleolytic activities mentioned above; (ii) one strain which was strongly impaired in the 13,000- and 26,000-molecular-weight activities, but showed a considerable level of the 15,000-molecular-weight activity; and (iii) three strains which were severely impaired in all three activities. The results indicated that the 26,000-molecular-weight activity was a dimer of the 13,000-molecular-weight activity and that this nuclease was involved in the entry of DNA.
在含DNA的十二烷基硫酸钠 - 聚丙烯酰胺凝胶中，对枯草芽孢杆菌感受态和生理低感受态野生型培养物中的核酸分解活性进行比较，结果显示存在三种与感受态相关的核酸酶活性，其表观分子量分别为13,000、15,000和26,000。这三种活性依赖于锰离子或镁离子，且特异性地存在于感受态培养物的感受态组分中。对八个转化缺陷型突变菌株的感受态相关核酸分解活性进行了测定，结果得到以下三类突变体：（i）根据此测定，有四个菌株在上述任何核酸分解活性方面均未受损；（ii）有一个菌株在分子量为13,000和26,000的活性方面严重受损，但显示出相当水平的分子量为15,000的活性；（iii）有三个菌株在所有三种活性方面均严重受损。结果表明，分子量为26,000的活性是分子量为13,000的活性的二聚体，并且这种核酸酶参与了DNA的进入。
