6m9g | pdb_00006m9g

BbvCI B2 dimer with Ta6Br14 clusters

spinqualitylabelsall models 6m9g, resolution 2.35Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6m9g is a 2 chain structure with sequence from Brevibacillus brevis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.35Å Ligands: ACT, BR, EDO, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q5D6Y4_BREBE Publication Abstract from PubMed BbvCI, a Type IIT restriction endonuclease, recognizes and cleaves the seven base pair sequence 5'-CCTCAGC-3', generating 3-base, 5'-overhangs. BbvCI is composed of two protein subunits, each containing one catalytic site. Either site can be inactivated by mutation resulting in enzyme variants that nick DNA in a strand-specific manner. Here we demonstrate that the holoenzyme is labile, with the R1 subunit dissociating at low pH. Crystallization of the R2 subunit under such conditions revealed an elongated dimer with the two catalytic sites located on opposite sides. Subsequent crystallization at physiological pH revealed a tetramer comprising two copies of each subunit, with a pair of deep clefts each containing two catalytic sites appropriately positioned and oriented for DNA cleavage. This domain organization was further validated with single-chain protein constructs in which the two enzyme subunits were tethered via peptide linkers of variable length. We were unable to crystallize a DNA-bound complex; however, structural similarity to previously crystallized restriction endonucleases facilitated creation of an energy-minimized model bound to DNA, and identification of candidate residues responsible for target recognition. Mutation of residues predicted to recognize the central C:G base pair resulted in an altered enzyme that recognizes and cleaves CCTNAGC (N = any base). Structure, subunit organization and behavior of the asymmetric Type IIT restriction endonuclease BbvCI.,Shen BW, Doyle L, Bradley P, Heiter DF, Lunnen KD, Wilson GG, Stoddard BL Nucleic Acids Res. 2019 Jan 10;47(1):450-467. doi: 10.1093/nar/gky1059. PMID:30395313 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Endonuclease 3D structures

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