2oxv

Structure of the A138T promiscuous mutant of the EcoRI restriction endonuclease bound to its cognate recognition site.

spinqualitylabelsall models 2oxv, resolution 1.95Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2oxv is a 2 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.95Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function T2E1_ECOLX Recognizes the double-stranded sequence GAATTC and cleaves after G-1. Publication Abstract from PubMed Promiscuous mutant EcoRI endonucleases bind to the canonical site GAATTC more tightly than does the wild-type endonuclease, yet cleave variant (EcoRI(*)) sites more rapidly than does wild-type. The crystal structure of the A138T promiscuous mutant homodimer in complex with a GAATTC site is nearly identical to that of the wild-type complex, except that the Thr138 side chains make packing interactions with bases in the 5'-flanking regions outside the recognition hexanucleotide while excluding two bound water molecules seen in the wild-type complex. Molecular dynamics simulations confirm exclusion of these waters. The structure and simulations suggest possible reasons why binding of the A138T protein to the GAATTC site has DeltaS degrees more favorable and DeltaH degrees less favorable than for wild-type endonuclease binding. The interactions of Thr138 with flanking bases may permit A138T, unlike wild-type enzyme, to form complexes with EcoRI(*) sites that structurally resemble the specific wild-type complex with GAATTC. Structural and thermodynamic basis for enhanced DNA binding by a promiscuous mutant EcoRI endonuclease.,Sapienza PJ, Rosenberg JM, Jen-Jacobson L Structure. 2007 Nov;15(11):1368-82. PMID:17997963 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Endonuclease 3D structures

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