1j5f

Theoretical Model: The protein structure described on this page was determined theoretically, and hence should be interpreted with caution.

REVISED MODEL OF T5 5' NUCLEASE + DNA

spinqualitylabelsall models 1j5f Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, PDBsum, ProSAT Publication Abstract from PubMed Previous structural studies on native T5 5' nuclease, a member of the flap endonuclease family of structure-specific nucleases, demonstrated that this enzyme possesses an unusual helical arch mounted on the enzyme's active site. Based on this structure, the protein's surface charge distribution, and biochemical analyses, a model of DNA binding was proposed in which single-stranded DNA threads through the archway. We investigated the kinetic and substrate-binding characteristics of wild-type and mutant nucleases in relation to the proposed model. Five basic residues R33, K215, K241, R172, and R216, are all implicated in binding branched DNA substrates. All these residues except R172 are involved in binding to duplex DNA carrying a 5' overhang. Replacement of either K215 or R216 with a neutral amino acid did not alter kcat appreciably. However, these mutant nucleases displayed significantly increased values for Kd and Km. A comparison of flap endonuclease binding to pseudoY substrates and duplexes with a single-stranded 5' overhang suggests a better model for 5' nuclease-DNA binding. We propose a major revision to the binding model consistent with these biophysical data. Interactions of mutant and wild-type flap endonucleases with oligonucleotide substrates suggest an alternative model of DNA binding.,Dervan JJ, Feng M, Patel D, Grasby JA, Artymiuk PJ, Ceska TA, Sayers JR Proc Natl Acad Sci U S A. 2002 Jun 25;99(13):8542-7. PMID:12084915 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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