[An analysis of methyltransferase SsoII-DNA contacts in the enzyme-substrate complex].
The functional groups of the DNA methylation site that are involved in the DNA interaction with methyltransferase SsoII at the recognition stage were identified. The contacts in the enzyme-substrate complex were analyzed in the presence of S-adenosyl-L-homocysteine using the interference footprinting assay with formic acid, hydrazine, dimethyl sulfate, or N-ethyl-N-nitrosourea as a modifying reagent. It was shown that the replacement of the central A.T by the G.C pair in the methylation site did not affect the enzyme-DNA interaction, whereas the use of a substrate with one chain methylated (monomethylated substrate) instead of the unmethylated substrate dramatically changes the DNA contacts. The binding constants of unmethylated and monomethylated substrates with methyltransferase SsoII in the presence of S-adenosyl-L-homocysteine were calculated.
Vorob'eva
O V
OV
Belozersky Institute of Physicochemical Biology, Moscow State University, Vorob'evy gory, Moscow, 119992 Russia.
Kariagina
A S
AS
Volkov
E M
EM
Viriasov
M B
MB
Oretskaia
T S
TS
Kubareva
E A
EA
D000595:Amino Acid Sequence; D001345:Autoradiography; D004247:DNA / Q000378:metabolism*; D018983:DNA Footprinting; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000378:metabolism; D015257:DNA-Cytosine Methylases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009692:Nucleic Acid Heteroduplexes / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D013379:Substrate Specificity
D004268:DNA-Binding Proteins; D009692:Nucleic Acid Heteroduplexes; D004247:DNA; C063974:DNA modification methylase SsoII; D015257:DNA-Cytosine Methylases