1wkq
From Proteopedia
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Crystal Structure of Bacillus subtilis Guanine Deaminase. The first domain-swapped structure in the cytidine deaminase superfamily
Overview
Guanine deaminase, a key enzyme in the nucleotide metabolism, catalyzes, the hydrolytic deamination of guanine into xanthine. The crystal structure, of the 156-residue guanine deaminase from Bacillus subtilis has been, solved at 1.17-A resolution. Unexpectedly, the C-terminal segment is, swapped to form an intersubunit active site and an intertwined dimer with, an extensive interface of 3900 A(2) per monomer. The essential zinc ion is, ligated by a water molecule together with His(53), Cys(83), and Cys(86). A, transition state analog was modeled into the active site cavity based on, the tightly bound imidazole and water molecules, allowing identification, of the conserved deamination mechanism and specific substrate recognition, by Asp(114) and Tyr(156'). The closed conformation also reveals that, substrate binding seals the active site entrance, which is controlled by, the C-terminal tail. Therefore, the domain swapping has not only, facilitated the dimerization but has also ensured specific substrate, recognition. Finally, a detailed structural comparison of the cytidine, deaminase superfamily illustrates the functional versatility of the, divergent active sites found in the guanine, cytosine, and cytidine, deaminases and suggests putative specific substrate-interacting residues, for other members such as dCMP deaminases.
About this Structure
1WKQ is a Single protein structure of sequence from Bacillus subtilis with ZN and IMD as ligands. Active as Guanine deaminase, with EC number 3.5.4.3 Full crystallographic information is available from OCA.
Reference
Crystal structure of Bacillus subtilis guanine deaminase: the first domain-swapped structure in the cytidine deaminase superfamily., Liaw SH, Chang YJ, Lai CT, Chang HC, Chang GG, J Biol Chem. 2004 Aug 20;279(34):35479-85. Epub 2004 Jun 4. PMID:15180998
Page seeded by OCA on Wed Nov 21 05:29:48 2007
