Reverse Transcriptase: Correlation of Zinc Content with Activity
AUTOR(ES)
Poiesz, Bernard J.
RESUMO
Evidence is presented that DNA polymerase of avian myeloblastosis virus has an obligatory zinc requirement for activity. Previous studies indicate that the purified polymerase contains zinc in a stoichiometry of about 1 g-atom/mole. We now find that the enzyme-bound zinc is exchangeable with radioactive 65Zn; after isoelectric focusing, the radioactive 65Zn is coincident with polymerase activity. Dialysis of the 65Zn-labeled polymerase against the chelator, 1,10-phenanthroline, results in a progressive loss of radioactive 65Zn and polymerase activity. Thereupon, incubation of the inactivated enzyme with Zn2+ fully restores activity. Thus, the DNA polymerase present in an oncogenic RNA virus, like animal DNA polymerases, can be rigorously classified as a zinc metalloenzyme. DNA polymerase of avian myeloblastosis virus is inactivated by 1,10-phenanthroline at a much faster rate than the bacterial and animal DNA polymerases that have been tested. It may, therefore, be possible to inactivate selectively DNA polymerases from animal tumor viruses by brief exposure to appropriate metal chelators.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=434005Documentos Relacionados
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