title: Cleavage of single-stranded DNA by the A and A* proteins of bacteriophage phi X174.
abstract: The purified A protein and A* protein of bacteriophage phi X174 have been tested for endonuclease activity on single stranded viral phi X174 DNA. The A protein (55.000 daltons) nicks single-stranded DNA in the same way and at the same place as it does superhelical RFI DNA, at the origin of DNA replication. The A* protein (37.000 daltons) can cleave the single-stranded viral DNA at many different sites. It has however a strong preference for the origin of replication. Both proteins generate 3'OH ends and blocked 5' termini at the nick site.
mesh_terms: D010584:Bacteriophage phi X 174 / Q000201:enzymology*; D001483:Base Sequence; D004254:DNA Nucleotidyltransferases / Q000378:metabolism; D004277:DNA, Single-Stranded; D004278:DNA, Superhelical; D003851:Deoxyribonucleases / Q000378:metabolism*; D004720:Endonucleases / Q000378:metabolism*; D008970:Molecular Weight; D013379:Substrate Specificity; D014764:Viral Proteins / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D004277:DNA, Single-Stranded; D004278:DNA, Superhelical; D014764:Viral Proteins; D004254:DNA Nucleotidyltransferases; D003851:Deoxyribonucleases; D004720:Endonucleases