ATP Dependent Deoxyribonuclease of Bacillus Subtilis; Subunit Structure and Substrate Specificity Of DNA Dependent -ATPase Activity

Abstract

ATP dependent deoxyribonucleases have been found in several bacterial species: Micrococcus luteus(1),Escherichia coZi (2,5), Diplococcus pneumoniae(6), Haemophilus influenzas (7.10),Mycobacterium smegmatis (II), Bacillus laterosporus (12) and Bacillus sub tilis 13–15). Evidence exists that this enzyme may be involved in genetic recombination. E.coli K12 recB and recC mutants which lack activity of the enzyme are defective in genetic recombination and DNA repair. Absence of the recB recC DNase was also found to be important in determining transformability (16). The level of genetic transformation is decreased in ATP dependent nuclease mutants of Diplococcus pneumoniae (6), but in H.influenzae, the role of the ATP dependent nuclease in recombination is not clear as mutants lacking this enzyme activity still keep their ability to recombine. The ATP dependent DNases purified from E.coli, M.Zuteus and H.influenzae have both exonucleolytic and endonucleolytic activity. They can degrade both single stranded and double stranded DNA from either the 3’ or the 5’ end and also possess a DNA dependent ATPase activity.