Role of DNA minor groove interactions in substrate recognition by the M.SinI and M.EcoRII DNA (cytosine-5) methyltransferases.

ABSTRACT: The SinI and EcoRII DNA methyltransferases recognize sequences (GG(A)/(T)CC and CC(A)/(T)GG, respectively), which are characterized by an (A)/(T) ambiguity. Recognition of the A.T and T.A base pair was studied by in vitro methyltransferase assays using oligonucleotide substrates containing a hypoxanthine.C base pair in the central position of the recognition sequence. Both enzymes methylated the substituted oligonucleotide with an efficiency that was comparable to methylation of the canonical substrate. These observations indicate that M.SinI and M.EcoRII discriminate between their canonical recognition site and the site containing a G.C or a C.G base pair in the center of the recognition sequence (GG(G)/(C)CC and CC(G)/(C)GG, respectively) by interaction(s) in the DNA minor groove. M.SinI

SUBMITTER: Kiss A 

PROVIDER: S-EPMC55819 | biostudies-literature | 2001 Aug

REPOSITORIES: biostudies-literature