枯草芽孢杆菌的ATP依赖性脱氧核糖核酸酶复合物(AddAB)具有两个共有的ATP结合序列,位于两个亚基的N末端区域。两个共有ATP结合序列中高度保守的赖氨酸残基被甘氨酸取代,产生突变酶复合物AddAB-A-K36G(AddA*B)和AddAB-B-K14G(AddAB*)。亚基AddA中的突变减少了DNA修复和染色体转化,并废除了噬菌体PBS1介导的转导。该突变还导致ATP依赖性外切核酸酶和解旋酶活性的完全丧失。相比之下,亚基AddB的突变仅有边际影响.用质粒DNA转化不需要recF和addAB基因,但在与染色体DNA的转化中具有重叠的活性。与RecF相比,AddAB酶对于PBS1介导的转导是必需的。然而,recF在DNA修复方面比addAB具有更重要的功能。
The ATP-dependent deoxyribonuclease enzyme complex (AddAB) of Bacillus subtilis possesses two
consensus ATP-binding sequences, located in the N-terminal region of both subunits. The highly conserved lysine residues in both
consensus ATP-binding sequences were replaced by glycine, resulting in the mutant enzyme complexes AddAB-A-K36G (AddA*B) and AddAB-B-K14G (AddAB*). The mutation in subunit AddA reduced DNA repair and chromosomal transformation, and abolished bacteriophage PBS1-mediated transduction. This mutation also resulted in a complete loss of the ATP-dependent exonuclease and helicase activity. In contrast, the mutation in subunit AddB had only marginal effects. The recF and addAB genes are not required for transformation with plasmid DNA, but have overlapping activities in transformation with chromosomal DNA. By contrast to RecF, the AddAB enzyme is essential for PBS1-mediated transduction. However, recF has a more important function with respect to DNA repair than addAB.