Open AccessDNA endonucleases associated with the avian myeloblastosis virus DNA polymerase.
Author(s) -
Kenneth P. Samuel,
Takis S. Papas,
Jack G. Chirikjian
Publication year - 1979
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.76.6.2659
Subject(s) - dna polymerase , polymerase , microbiology and biotechnology , dna polymerase ii , rnase h , dna clamp , endonuclease , dna , rna directed dna polymerase , dna polymerase i , reverse transcriptase , primase , biology , virology , chemistry , biochemistry , rna , gene
A DNA endonuclease, Endo-I, which cleaves superhelical DNAs, has been isolated from avian myeloblastosis virions stripped of their coats by mild detergent treatment. The enzyme has a broad pH optimum around 7.5-8.0 and requires Mg2+ for activity. A second endonuclease, Endo-II, with a requirement for Mn2+, also present in viral cores, copurified with avian myeloblastosis virus alpha beta DNA polymerase (reverse transcriptase, RNA-dependent DNA nucleotidyltransferase) and similarly cleaved superhelical DNAs. Heat denaturation and sodium fluoride and N-ethylmaleimide inhibition studies were carried out to demonstrate a possible relationship between the two endonucleases and the viral DNA polymerase and RNase H activities. It appears that Endo-II may be an intrinsic activity of the polymerase.