NaF and mononucleotides as inhibitors of 3'-5'-exonuclease activity and stimulators of polymerase activity of E. coli DNA polymerase I Klenow fragment.
It has been shown that, in the absence of dATP in the poly(dT).oligo(dA) template-primer complex, the rate of primer cleavage by the E. coli DNA polymerase I Klenow fragment equals 4% of polymerization rate, while in the presence of dATP it equals as much as 50-60%. NaF and NMP taken separately inhibit exonuclease cleavage of oligo(dA) both with and without dATP. The addition of NaF (5-10 mM) or NMP (5-20 mM) increases the absolute increment of polymerization rate 5-9-fold relative to the absolute decrement of the rate of nuclease hydrolysis of primer. This proves the assumption that not more than 10-20% of primer molecules, interacting with the exonuclease center of polymerase, are cleaved by the enzyme. Presumably, NaF and nucleotides disturb the coupling of the 3'-end of oligonucleotide primer to the exonuclease center of the enzyme. As the primers mostly form complexes with the polymerizing center, the reaction of polymerization is activated.
Potapova
I A
IA
Novosibirsk Institute of Bioorganic Chemistry, Siberian Division of the USSR Academy of Sciences.
Nevinsky
G A
GA
Khomov
V V
VV
Lavrik
O I
OI
D004256:DNA Polymerase I / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D003838:Deoxyadenine Nucleotides / Q000494:pharmacology; D003854:Deoxyribonucleotides / Q000494:pharmacology; D005090:Exodeoxyribonucleases / Q000037:antagonists & inhibitors*; D066298:In Vitro Techniques; D012969:Sodium Fluoride / Q000494:pharmacology*; D013698:Templates, Genetic
D003838:Deoxyadenine Nucleotides; D003854:Deoxyribonucleotides; D012969:Sodium Fluoride; D004256:DNA Polymerase I; D005090:Exodeoxyribonucleases