title: Reverse transcriptase-associated ribonuclease H does not require zinc for catalysis.
abstract: omicron-Phenanthroline, a zinc chelating agent, is known to inhibit the DNA polymerase activity of cellular DNA-dependent and viral RNA-dependent DNA polymerases. We find that omicron-phenanthroline does not inhibit the reverse transcriptase-associated RNase H activity of retroviruses. Kinetic studies, using DNA template-primers as an inhibitor of RNase H, suggest that zinc does not play any role in template-primer binding by reverse transcriptase. These results also indicate a distinct binding site for the template and triphosphate substrates. Cellular RNase H from calf thymus and RNase H-II from Rauscher leukemia virus are likewise resistant to omicron-phenanthroline inhibition, implying non-involvement of zinc in the nucleic acid hydrolysis by these enzymes.
mesh_terms: D009189:Avian Myeloblastosis Virus / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D004720:Endonucleases / Q000378:metabolism*; D007700:Kinetics; D009858:Oncogenic Viruses / Q000201:enzymology; D010618:Phenanthrolines / Q000494:pharmacology; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism*; D012260:Ribonucleases / Q000378:metabolism*; D015032:Zinc / Q000494:pharmacology*
chemical_list: D010618:Phenanthrolines; D012194:RNA-Directed DNA Polymerase; D004259:DNA-Directed DNA Polymerase; D004720:Endonucleases; D012260:Ribonucleases; D015032:Zinc