5hnk

Crystal structure of T5Fen in complex intact substrate and metal ions.

spinqualitylabelsall models 5hnk, resolution 2.22Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5hnk is a 4 chain structure with sequence from Escherichia virus T5 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 2.22Å Ligands: GOL, K, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function FEN_BPT5 Catalyzes both the 5'-exonucleolytic and structure-specific endonucleolytic hydrolysis of DNA branched nucleic acid molecules and probably plays a role in viral genome replication (PubMed:9874768, PubMed:15077103, PubMed:10364212). Active on flap (branched duplex DNA containing a free single-stranded 5'-end), 5'overhangs and pseudo-Y structures (PubMed:9874768, PubMed:15077103, PubMed:10364212). The substrates require a free, single-stranded 5' end, with endonucleolytic hydrolysis occurring at the junction of double- and single-stranded DNA (PubMed:9874768). This function may be used for example to trim such branched molecules generated by Okazaki fragments synthesis during replication.[HAMAP-Rule:MF_04140] Publication Abstract from PubMed Maintenance of genome integrity requires that branched nucleic acid molecules be accurately processed to produce double-helical DNA. Flap endonucleases are essential enzymes that trim such branched molecules generated by Okazaki-fragment synthesis during replication. Here, we report crystal structures of bacteriophage T5 flap endonuclease in complexes with intact DNA substrates and products, at resolutions of 1.9-2.2 A. They reveal single-stranded DNA threading through a hole in the enzyme, which is enclosed by an inverted V-shaped helical arch straddling the active site. Residues lining the hole induce an unusual barb-like conformation in the DNA substrate, thereby juxtaposing the scissile phosphate and essential catalytic metal ions. A series of complexes and biochemical analyses show how the substrate's single-stranded branch approaches, threads through and finally emerges on the far side of the enzyme. Our studies suggest that substrate recognition involves an unusual 'fly-casting, thread, bend and barb' mechanism. Direct observation of DNA threading in flap endonuclease complexes.,AlMalki FA, Flemming CS, Zhang J, Feng M, Sedelnikova SE, Ceska T, Rafferty JB, Sayers JR, Artymiuk PJ Nat Struct Mol Biol. 2016 Jun 6. doi: 10.1038/nsmb.3241. PMID:27273516 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Exonuclease 3D structures

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