title: Structure of a nicked DNA-protein complex isolated from simian virus 40: covalent attachment of the protein to DNA and nick specificity.
abstract: A portion of the nicked circular DNA isolated from purified simian virus 40 contains a protein-DNA complex in which protein(s) is covalently attached to the end of a DNA single strand. (Nicked DNA is double-stranded DNA that contains at least one single-strand scission.) The protein was visualized by electron microscopy and labeled in vitro with 125I. The bond between the protein and the DNA is stable in alkali, 4 M guanidine-hydrochloride, 3.86 M hydroxylamine (pH 4,23), and in 98% formamide. Most of the molecules in the nicked circular DNA fraction contained one nick. The nick occurs on either of the two complementary strands; the specific nick sites on the two strands are staggered, but lie within a few hundred nucleotides of each other.
mesh_terms: D004270:DNA, Circular; D004279:DNA, Viral; D003852:Deoxyribonucleoproteins; D008854:Microscopy, Electron; D009691:Nucleic Acid Denaturation; D009695:Nucleic Acid Renaturation; D009698:Nucleoproteins; D013539:Simian virus 40 / Q000648:ultrastructure*; D014764:Viral Proteins
chemical_list: D004270:DNA, Circular; D004279:DNA, Viral; D003852:Deoxyribonucleoproteins; D009698:Nucleoproteins; D014764:Viral Proteins