[RNA-dependent DNA-polymerase from avian myeloblastosis virus: effectiveness of interaction with oligothymidylate primers of various length]

Mol Biol (Mosk). Mar-Apr 1990;24(2):396-407.
[Article in Russian]

Abstract

Optimal conditions for the reaction of polymerization catalyzed by RNA-dependent DNA-polymerase from AMV on poly(A)- and poly(dA)-templates with d(pT)n-primers were established. Optimal concentrations of the components and pH of the reaction mixtures were found out to differ significantly. dTTP was shown to be both a nucleotide substrate and a minimal primer of the polymerization. The Km values for d(pT)2-primer (Km = 0.11 mM and 0.54 for poly(A) and poly(dA)-templates, respectively) and longer oligothymidylates were estimated. The lengthening of d(pT)n (n = 2-10) by one mononucleotide unit led to a 3-fold and 2-fold decrease of Km value for poly(A) and poly(dA), respectively. Further lengthening of the primer (n = 10-25) did not affect Km for the primers. The maximal rates of polymerization did not depend on primer length. The activation reaction (Ea = 12 kcal/mol) of polymerization on poly(A) was considerably lower than that on poly(dA) (Ea = 50 kcal/mol). In both cases a highly processive polymerization was observed. It was suggested that the synthesis had been more effective on poly(A)-template due to a more effective formation of the complex enzyme primer template.

Publication types

  • English Abstract

MeSH terms

  • Avian Leukosis Virus / enzymology*
  • Avian Myeloblastosis Virus / enzymology*
  • Avian Myeloblastosis Virus / genetics
  • Catalysis
  • Hydrogen-Ion Concentration
  • Kinetics
  • Poly A / metabolism*
  • Poly T / metabolism*
  • Polydeoxyribonucleotides / metabolism*
  • RNA-Directed DNA Polymerase / genetics
  • RNA-Directed DNA Polymerase / metabolism*
  • Templates, Genetic

Substances

  • Polydeoxyribonucleotides
  • Poly A
  • Poly T
  • poly(dA)
  • RNA-Directed DNA Polymerase