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Publication Abstract from PubMed

DNA-adenine methylation at certain GATC sites plays a pivotal role in bacterial and phage gene expression as well as bacterial virulence. We report here the crystal structures of the bacteriophage T4Dam DNA adenine methyltransferase (MTase) in a binary complex with the methyl-donor product S-adenosyl-L-homocysteine (AdoHcy) and in a ternary complex with a synthetic 12-bp DNA duplex and AdoHcy. T4Dam contains two domains: a seven-stranded catalytic domain that harbors the binding site for AdoHcy and a DNA binding domain consisting of a five-helix bundle and a beta-hairpin that is conserved in the family of GATC-related MTase orthologs. Unexpectedly, the sequence-specific T4Dam bound to DNA in a nonspecific mode that contained two Dam monomers per synthetic duplex, even though the DNA contains a single GATC site. The ternary structure provides a rare snapshot of an enzyme poised for linear diffusion along the DNA.

Structure of the bacteriophage T4 DNA adenine methyltransferase.,Yang Z, Horton JR, Zhou L, Zhang XJ, Dong A, Zhang X, Schlagman SL, Kossykh V, Hattman S, Cheng X Nat Struct Biol. 2003 Oct;10(10):849-55. Epub 2003 Aug 24. PMID:12937411^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.