Crystal structures of yeast beta-alanine synthase complexes reveal the mode of substrate binding and large scale domain closure movements
Author
Summary, in English
β-Alanine synthase is the final enzyme of the reductive pyrimidine catabolic pathway, which is responsible for the breakdown of uracil and thymine in higher organisms. The fold of the homodimeric enzyme from the yeast Saccharomyces kluyveri identifies it as a member of the AcyI/M20 family of metallopeptidases. Its subunit consists of a catalytic domain harboring a di-zinc center and a smaller dimerization domain. The present site-directed mutagenesis studies identify Glu159 and Arg322 as crucial for catalysis and His262 and His397 as functionally important but not essential. We determined the crystal structures of wild-type β-alanine synthase in complex with the reaction product β-alanine, and of the mutant E159A with the substrate N-carbamyl-β-alanine, revealing the closed state of a dimeric AcyI/M20 metallopeptidase-like enzyme. Subunit closure is achieved by a 30° rigid body domain rotation, which completes the active site by integration of substrate binding residues that belong to the dimerization domain of the same or the partner subunit. Substrate binding is achieved via a salt bridge, a number of hydrogen bonds, and coordination to one of the zinc ions of the di-metal center.
Department/s
Publishing year
2007
Language
English
Pages
36037-36047
Publication/Series
Journal of Biological Chemistry
Volume
282
Issue
49
Document type
Journal article
Publisher
American Society for Biochemistry and Molecular Biology
Topic
- Biological Sciences
Keywords
- nucleic acid precursors
- structure-function
- catabolism
Status
Published
ISBN/ISSN/Other
- ISSN: 1083-351X