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Crystal Structure of C71S Mutant of DNA Cytosine-5 Methyltransferase M.HaeIII Bound to DNACrystal Structure of C71S Mutant of DNA Cytosine-5 Methyltransferase M.HaeIII Bound to DNA
Structural highlights
Function[MTH3_HAEAE] This methylase recognizes the double-stranded sequence GGCC, causes specific methylation on C-3 on both strands, and protects the DNA from cleavage by the HaeIII endonuclease. Publication Abstract from PubMedEpigenetic methylation of cytosine residues in DNA is an essential element of genome maintenance and function in organisms ranging from bacteria to humans. DNA 5-cytosine methyltransferase enzymes (DCMTases) catalyze cytosine methylation via reaction intermediates in which the DNA is drastically remodeled, with the target cytosine residue extruded from the DNA helix and plunged into the active site pocket of the enzyme. We have determined a crystal structure of M.HaeIII DCMTase in complex with its DNA substrate at a previously unobserved state, prior to extrusion of the target cytosine and frameshifting of the DNA recognition sequence. The structure reveals that M.HaeIII selects the target cytosine and destabilizes its base-pairing through a precise, focused, and coordinated assault on the duplex DNA, which isolates the target cytosine from its nearest neighbors and thereby facilitates its extrusion from DNA. Structural origins of DNA target selection and nucleobase extrusion by a DNA Cytosine methyltransferase.,Didovyk A, Verdine GL J Biol Chem. 2012 Nov 23;287(48):40099-105. doi: 10.1074/jbc.M112.413054. Epub, 2012 Sep 25. PMID:23012373[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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