Nucleic Acids Research, 1984, Vol. 12, No. 8 3695-3706
© 1984
ENZYMOLOGY |
Butylphenyl dGTP: a selective and potent inhibitor of mammalian DNA polymerase alpha
Department of Pharmacology, University of Massachusetts Medical School Worcester, MA 01605, USA
Received January 16, 1984. Revised March 21, 1984. Accepted March 21, 1984.
BuPdGTP, the 2'-deoxyribonucleoside 5'-triphosphate of the DNA polymerase alpha (pol 
)-specific inhibitor, N2-(p-n-butylphenyl) guanine, was examined with respect to its mechanism and its capacity to inhibit the mammalian DNA polymerases, pol , pol , and pol 
. BuPdGTP was specifically inhibitory for pol , with no discernible activity on pol ß and pol . The potency of BuPdGTP is unprecedented, with an apparent Ki less than 10 nanomolar. The unusual potency of the BuPdGTP is derived primarily from the 5' and ß phosphoryl moieties, whose binding to enzyme complements that of the base-linked butylphenyl substituent. BuPdGTP is competitive with dGTP and apparently not subject to polymerization. Experiments employing BuPdGTP in the presence of a non-complementary template suggest that the core polymerase or an associated coprotein contains dNTP binding sites which recognize specific nucleic acid bases. The partial sensitivity of selected, non-mammalian DNA polymerases suggests that modification of the N2 substituent of dGTP will be a useful route to the design of novel, polymerase-specific affinity-probes.