3ldy | pdb_00003ldy

An extraordinary mechanism of DNA perturbation exhibited by the rare-cutting HNH restriction endonuclease PacI

spinqualitylabelsall models 3ldy, resolution 1.97Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3ldy is a 3 chain structure with sequence from Atcc 14909. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CA, ZN Related: 3m7k Gene: pacIR (ATCC 14909) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed The crystal structure of the rare-cutting HNH restriction endonuclease PacI in complex with its eight-base-pair target recognition sequence 5'-TTAATTAA-3' has been determined to 1.9 A resolution. The enzyme forms an extended homodimer, with each subunit containing two zinc-bound motifs surrounding a betabetaalpha-metal catalytic site. The latter is unusual in that a tyrosine residue likely initiates strand cleavage. PacI dramatically distorts its target sequence from Watson-Crick duplex DNA base pairing, with every base separated from its original partner. Two bases on each strand are unpaired, four are engaged in noncanonical A:A and T:T base pairs, and the remaining two bases are matched with new Watson-Crick partners. This represents a highly unusual DNA binding mechanism for a restriction endonuclease, and implies that initial recognition of the target site might involve significantly different contacts from those visualized in the DNA-bound cocrystal structures. Unusual target site disruption by the rare-cutting HNH restriction endonuclease PacI.,Shen BW, Heiter DF, Chan SH, Wang H, Xu SY, Morgan RD, Wilson GG, Stoddard BL Structure. 2010 Jun 9;18(6):734-43. PMID:20541511 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Endonuclease

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