6t21

N-terminal domain of EcoKMcrA restriction endonuclease (NEco) in complex with T5mCGA target sequence

spinqualitylabelsall models 6t21, resolution 2.07Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6t21 is a 6 chain structure with sequence from Escherichia coli K-12 and Synthetic construct. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.07Å Ligands: 5CM Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function MCRA_ECOLI Restriction of 5-methyl and 5-hydroxymethylcytosines at the specific DNA sequence C(me)CGG. Publication Abstract from PubMed EcoKMcrA from Escherichia coli restricts CpG methylated or hydroxymethylated DNA, and may act as a barrier against host DNA. The enzyme consists of a novel N-terminal specificity domain that we term NEco, and a C-terminal catalytic HNH domain. Here, we report that NEco and full-length EcoKMcrA specificities are consistent. NEco affinity to DNA increases more from hemi- to full-methylation than from non- to hemi-methylation, indicating cooperative binding of the methyl groups. We determined the crystal structures of NEco in complex with fully modified DNA containing three variants of the Y5mCGR EcoKMcrA target sequence: C5mCGG, T5mCGA and T5hmCGA. The structures explain the specificity for the two central base pairs and one of the flanking pairs. As predicted based on earlier biochemical experiments, NEco does not flip any DNA bases. The proximal and distal methyl groups are accommodated in separate pockets. Changes to either pocket reduce DNA binding by NEco and restriction by EcoKMcrA, confirming the relevance of the crystallographically observed binding mode in solution. Crystal structure of the EcoKMcrA N-terminal domain (NEco): recognition of modified cytosine bases without flipping.,Slyvka A, Zagorskaite E, Czapinska H, Sasnauskas G, Bochtler M Nucleic Acids Res. 2019 Nov 14. pii: 5625526. doi: 10.1093/nar/gkz1017. PMID:31724709 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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