1r3n
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(New page: 200px<br /><applet load="1r3n" size="450" color="white" frame="true" align="right" spinBox="true" caption="1r3n, resolution 2.70Å" /> '''Crystal structure of...)
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Revision as of 19:55, 24 November 2007
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Crystal structure of beta-alanine synthase from Saccharomyces kluyveri
Overview
beta-Alanine synthase (beta AS) is the final enzyme of the reductive, pyrimidine catabolic pathway, which is responsible for the breakdown of, pyrimidine bases, including several anticancer drugs. In eukaryotes, beta, ASs belong to two subfamilies, which exhibit a low degree of sequence, similarity. We determined the structure of beta AS from Saccharomyces, kluyveri to a resolution of 2.7 A. The subunit of the homodimeric enzyme, consists of two domains: a larger catalytic domain with a dizinc metal, center, which represents the active site of beta AS, and a smaller domain, mediating the majority of the intersubunit contacts. Both domains exhibit, a mixed alpha/beta-topology. Surprisingly, the observed high structural, homology to a family of dizinc-dependent exopeptidases suggests that these, two enzyme groups have a common origin. Alterations in the ligand, composition of the metal-binding site can be explained as adjustments to, the catalysis of a different reaction, the hydrolysis of an N-carbamyl, bond by beta AS compared with the hydrolysis of a peptide bond by, exopeptidases. In contrast, there is no resemblance to the, three-dimensional structure of the functionally closely related, N-carbamyl-d-amino acid amidohydrolases. Based on comparative structural, analysis and observed deviations in the backbone conformations of the, eight copies of the subunit in the asymmetric unit, we suggest that, conformational changes occur during each catalytic cycle.
About this Structure
1R3N is a Single protein structure of sequence from Lachancea kluyveri with ZN and BIB as ligands. Active as Beta-ureidopropionase, with EC number 3.5.1.6 Full crystallographic information is available from OCA.
Reference
Yeast beta-alanine synthase shares a structural scaffold and origin with dizinc-dependent exopeptidases., Lundgren S, Gojkovic Z, Piskur J, Dobritzsch D, J Biol Chem. 2003 Dec 19;278(51):51851-62. Epub 2003 Oct 8. PMID:14534321
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