Transformation in Bacillus subtilis: purification and partial characterization of a membrane-bound DNA-binding protein.
In DNA binding-deficient mutants of Bacillus subtilis a competence-specific protein with a subunit molecular weight of 18,000 was absent. The native protein containing this subunit was purified from B. subtilis membranes by chromatography on hydroxyapatite, DEAE-cellulose, and Sephacryl S-200. This protein appeared to be complexed with a second protein of slightly lower molecular weight (17,000) and a different isoelectric point. The native protein complex (apparent molecular weight, 75,000) contained approximately equal amounts of the two polypeptides and showed a strong DNA-binding activity. Incubation of the complex with plasmid and bacteriophage DNA revealed nuclease activity, specifically directed toward double-stranded DNA. Predominantly single-stranded nicks and a limited number of double-stranded breaks were introduced in the presence of Mg2+ ions. In the presence of Mn2+ ions the complex produced low-molecular-weight breakdown products from the DNA.
D001412:Bacillus subtilis / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000302:isolation & purification* / Q000378:metabolism; D004269:DNA, Bacterial / Q000378:metabolism; D004270:DNA, Circular / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000302:isolation & purification* / Q000378:metabolism; D003851:Deoxyribonucleases / Q000378:metabolism; D008970:Molecular Weight; D013379:Substrate Specificity; D014162:Transfection; D014169:Transformation, Bacterial
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004270:DNA, Circular; D004268:DNA-Binding Proteins; D003851:Deoxyribonucleases