4dkj | pdb_00004dkj

CpG specific methyltransferase in complex with target DNA

spinqualitylabelsall models 4dkj, resolution 2.15Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4dkj is a 3 chain structure with sequence from Malacoplasma penetrans HF-2. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: 5CM, C37, GOL, SAH Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [Q8EVR5_MALP2] Publication Abstract from PubMed Cytosine methylation promotes deamination. In eukaryotes, CpG methylation is thought to account for CpG underrepresentation. Whether scarcity of CpGs in prokaryotic genomes is diagnostic for methylation is not clear. Here, we report that Mycoplasms tend to be CpG depleted and to harbor a family of constitutively expressed or phase variable CpG-specific DNA methyltransferases. The very CpG poor Mycoplasma penetrans and its constitutively active CpG-specific methyltransferase M.MpeI were chosen for further characterization. Genome-wide sequencing of bisulfite-converted DNA indicated that M.MpeI methylated CpG target sites both in vivo and in vitro in a locus-nonselective manner. A crystal structure of M.MpeI with DNA at 2.15-A resolution showed that the substrate base was flipped and that its place in the DNA stack was taken by a glutamine residue. A phenylalanine residue was intercalated into the "weak" CpG step of the nonsubstrate strand, indicating mechanistic similarities in the recognition of the short CpG target sequence by prokaryotic and eukaryotic DNA methyltransferases. CpG underrepresentation and the bacterial CpG-specific DNA methyltransferase M.MpeI.,Wojciechowski M, Czapinska H, Bochtler M Proc Natl Acad Sci U S A. 2012 Dec 17. PMID:23248272 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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