2abk
From Proteopedia
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REFINEMENT OF THE NATIVE STRUCTURE OF ENDONUCLEASE III TO A RESOLUTION OF 1.85 ANGSTROM
Overview
The 1.85 A crystal structure of endonuclease III, combined with mutational, analysis, suggests the structural basis for the DNA binding and catalytic, activity of the enzyme. Helix-hairpin-helix (HhH) and [4Fe-4S] cluster, loop (FCL) motifs, which we have named for their secondary structure, bracket the cleft separating the two alpha-helical domains of the enzyme., These two novel DNA binding motifs and the solvent-filled pocket in the, cleft between them all lie within a positively charged and, sequence-conserved surface region. Lys120 and Asp138, both shown by, mutagenesis to be catalytically important, lie at the mouth of this, pocket, suggesting that this pocket is part of the active site. The, positions of the HhH motif and protruding FCL motif, which contains the, DNA binding residue Lys191, can accommodate B-form DNA, with a flipped-out, base bound within the active site pocket. The identification of HhH and, FCL sequence patterns in other DNA binding proteins suggests that these, motifs may be a recurrent structural theme for DNA binding proteins.
About this Structure
2ABK is a Single protein structure of sequence from Escherichia coli with SF4 as ligand. This structure superseeds the now removed PDB entry 1ABK. Active as DNA-(apurinic or apyrimidinic site) lyase, with EC number 4.2.99.18 Full crystallographic information is available from OCA.
Reference
Novel DNA binding motifs in the DNA repair enzyme endonuclease III crystal structure., Thayer MM, Ahern H, Xing D, Cunningham RP, Tainer JA, EMBO J. 1995 Aug 15;14(16):4108-20. PMID:7664751
Page seeded by OCA on Wed Nov 21 08:02:16 2007
