Open AccessCleavage and circularization of single-stranded DNA: a novel enzymatic activity ofφX174 A*protein
Author(s) -
Shlomo Esienberg,
Mitchell Finer
Publication year - 1980
Publication title -
nucleic acids research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.008
H-Index - 537
eISSN - 1362-4954
pISSN - 0305-1048
DOI - 10.1093/nar/8.22.5305
Subject(s) - phosphodiester bond , dna , biology , cleavage (geology) , covalent bond , microbiology and biotechnology , biochemistry , gel electrophoresis , dna clamp , enzyme , gene , chemistry , rna , paleontology , reverse transcriptase , organic chemistry , fracture (geology)
Purified phi X gene A* protein cleaves phi X single stranded DNA. The cleavage appears to be stoichiometric, whereby a gene A* protein molecule cleaves a phosphodiester bond and binds to the DNA fragment. The size of the cleavage product was inversely proportional to the ratio of A* protein to DNA in the reaction mixture. The cleavage of the DNA resulted in the formation of an A* protein - ssDNA complex identified on SDS-polyacrylamide gels and by banding in CsCl. An A* protein-ssDNA complex was isolated by gel filtration and shown to be active in a ligating reaction in which the two ends of the DNA fragment were joined to form a covalently closed circle. The joining reaction required Mg++ ions and was accompanied by the release of the protein from the DNA.