RNA-dependent ATPase from Saccharomyces cerevisiae.
A new RNA-dependent ATPase has been isolated from yeast chromatin extracts and partially characterized. The protein has a sedimentation coefficient of about 7 S. The enzyme hydrolyzes specifically ATP (or dATP) to ADP (or dADP) and Pi in the presence of Mg2+ or Mn2+ ions and requires a single-stranded polynucleotide as cofactor. The order of efficiency of synthetic polymers is poly(rU) > poly(rI) greater than or equal to poly(dU) > poly(rA) greater than or equal to poly(rC). Among natural polymers, single-stranded DNA and poly(rA)-containing mRNA from yeast are also active but less so than poly(rU). The enzyme exhibits a pH optimum of 8 and is fully inhibited by 0.25 M NaCl. The Km for ATP is0.2 mM. The resemblance between this ATPase and DNA-dependent ATPases from other sources, as well as the termination factor rho, is discussed.
D000251:Adenosine Triphosphatases / Q000302:isolation & purification / Q000378:metabolism*; D002843:Chromatin / Q000201:enzymology; D004277:DNA, Single-Stranded; D007700:Kinetics; D008970:Molecular Weight; D011119:Polynucleotides / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
D002843:Chromatin; D004277:DNA, Single-Stranded; D011119:Polynucleotides; D000251:Adenosine Triphosphatases; C027900:RNA-dependent ATPase