6ghs

Modification dependent TagI restriction endonuclease

spinqualitylabelsall models 6ghs, resolution 2.92Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6ghs is a 1 chain structure with sequence from Atcc 51797. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: NA, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed TagI belongs to the recently characterized SRA-HNH family of modification-dependent restriction endonucleases (REases) that also includes ScoA3IV (Sco5333) and TbiR51I (Tbis1). Here, we present a crystal structure of dimeric TagI, which exhibits a DNA binding site formed jointly by the nuclease domains, and separate binding sites for modified DNA bases in the two protomers. The nuclease domains have characteristic features of HNH/betabetaalpha-Me REases, and catalyze nicks or double strand breaks, with preference for /RY and RYN/RY sites, respectively. The SRA domains have the canonical fold. Their pockets for the flipped bases are spacious enough to accommodate 5-methylcytosine (5mC) or 5-hydroxymethylcytosine (5hmC), but not glucosyl-5-hydroxymethylcytosine (g5hmC). Such preference is in agreement with the biochemical determination of the TagI modification dependence and the results of phage restriction assays. The ability of TagI to digest plasmids methylated by Dcm (C5mCWGG), M.Fnu4HI (G5mCNGC) or M.HpyCH4IV (A5mCGT) suggests that the SRA domains of the enzyme are tolerant to different sequence contexts of the modified base. Crystal structure of the modification-dependent SRA-HNH endonuclease TagI.,Kisiala M, Copelas A, Czapinska H, Xu SY, Bochtler M Nucleic Acids Res. 2018 Sep 7. pii: 5091957. doi: 10.1093/nar/gky781. PMID:30202937 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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