3′-Deoxyribonucleotides Inhibit Eukaryotic DNA Primase

• Published in: Journal of biochemistry (Tokyo) Vol. 119; no. 6; pp. 1038 - 1044
• Main Authors: Izuta, Shunji, Kohsaka-Ichikawa, Mizue, Yamaguchi, Toyofumi, Saneyosh, Mineo
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.06.1996
• Subjects: 3′-deoxyribonucleotides; Animals; cherry salmon; Deoxyadenosines - pharmacology; Deoxyribonucleotides - pharmacology; DNA - biosynthesis; DNA Polymerase I - antagonists & inhibitors; DNA Polymerase II - antagonists & inhibitors; DNA Polymerase III - antagonists & inhibitors; DNA polymerase α family; DNA Primase; DNA Replication; Kinetics; Male; RNA - biosynthesis; RNA Nucleotidyltransferases - antagonists & inhibitors; Salmon; synthetic inhibitor; Testis - metabolism
• ISSN: 0021-924X
• DOI: 10.1093/oxfordjournals.jbchem.a021345

In order to elucidate the biological activities of cordycepin (3′-deoxyadenosine) and related 3′-deoxyribonucleosides on eukaryotic DNA replication, the inhibitory effects of triphosphate derivatives of 3′-deoxyadenosine (3′-dATP), 8-azido-3′-deoxyadenosine (8-N3-3′-dATP), 3′-deoxyguanosine (3′-dGTP), 3′-deoxyuridine (3′-dUTP), 5-fluoro-3′-deoxyuridine (5-F-3′-dUTP), 3′-deoxycytidine (3′-dCTP), and 5-fluoro-3′-deoxycytidine (5-F-3′-dCTP) on DNA primase and replicative DNA polymerases α, δ, and ε purified from cherry salmon (Oncorhynchus masou) testes or calf thymus were examined. All analogs, except 8-N3-3′-dATP, showed strong inhibitory effects on DNA primase, but none of them inhibited DNA polymerases α, δ, or ε. Kinetic analysis revealed that the inhibition modes of them were competitive with respect to the incorporation of natural substrate that had the corresponding base moiety and non-competitive with respect to other substrates. Based on the kinetic data, we compared the affinities of 3′-dNTPs between DNA primase and RNA polymerases I and II, since 3′-dNTPs also inhibit eukaryotic RNA polymerases. Although the K1 values for DNA primase were much larger than those for RNA polymerases, the K1/Km values, which indicate the affinity of the analog to the enzyme, were very similar.