[Interactions of human 8-oxoguanine-DNA glycosylase with single- and double-stranded DNA].
Interactions of human 8-oxoguanine-DNA glycosylase (hOGG1) with single- and double-stranded oligodeoxyribonucleotides (ODN) have been studied by the method of stepwise increase in ligand complexity. The ODNs have been found to inhibit the glycosylase-catalyzed reaction competitively. The K1 values have been determined for a set of ODNs. All units of non-specific DNA within the enzyme footprint have been shown to interact with the protein globule in an additive manner. An increase in the d(pN)n length (n) by one unit caused a monotonous 1.4-1.5-fold increase in their affinity for the glycosylase ODN until n = 10, mostly due to weak nonspecific contacts of the enzyme and the sugar-phosphate backbone. The weak nonspecific additive interactions contributed about five orders of magnitude in the affinity of hOGG1 for specific DNA (Kd approximately 10(-5) M), whereas introduction of a 8-oxoguanine residue added about three orders of magnitude to this affinity (Kd approximately 10(-8) M). Quantitative features of recognition of specific DNA by the enzyme are analyzed.
Kirpota
O O
OO
Zharkov
D O
DO
Buneva
V N
VN
Nevinskiĭ
G A
GA
D002384:Catalysis; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D045647:DNA Glycosylases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D009841:Oligonucleotides / Q000737:chemistry / Q000494:pharmacology; D013379:Substrate Specificity
D004277:DNA, Single-Stranded; D009841:Oligonucleotides; D004247:DNA; D045647:DNA Glycosylases; C479058:oxoguanine glycosylase 1, human