1hfb | pdb_00001hfb
CRYSTAL STRUCTURE OF THE TYROSINE-REGULATED 3-DEOXY-D-ARABINO-HEPTULOSONATE-7-PHOSPHATE SYNTHASE FROM SACCHAROMYCES CEREVISIAE COMPLEXED WITH PHOSPHOENOLPYRUVATE
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Overview
The betaalpha barrel is the common protein fold of numerous enzymes and was proposed recently to be the result of gene duplication and fusion of an ancient half-barrel. The initial enzyme of shikimate biosynthesis possesses the additional feature of feedback regulation. The crystal structure and kinetic studies on chimera and mutant proteins of yeast 3-deoxy-d-arabino-heptulosonate-7-phosphate (DAHP) synthase from Saccharomyces cerevisiae inhibited by phenylalanine (Aro3p) and DAHP synthase S. cerevisiae inhibited by tyrosine (Aro4p) give insight into important regions for regulation in the enzyme: The loop, which is connecting the two half-barrels, and structural elements added to the barrel are prerequisites for regulation and form a cavity on the N-terminal side of the betaalpha barrel. In the cavity of Aro4p at position 226 is a glycine residue, which is highly conserved in all other tyrosine-regulated DAHP synthases as well. Sequence alignments with phenylalanine-regulated DAHP synthases including Aro3p show a highly conserved serine residue at this position. An exchange of glycine to serine and vice versa leads to a complete change in the regulation pattern. Therefore the evolution of these differently feedback-inhibited isoenzymes required gene duplication and a single mutation within the internal extra element. Numerous additional amino acid substitutions present in the contemporary isoenzymes are irrelevant for regulation and occurred independently.
About this Structure
1HFB is a Single protein structure of sequence from Saccharomyces cerevisiae with PEP as ligand. Active as Transferred entry: 2.5.1.54, with EC number 4.1.2.15 Known structural/functional Site: AC1. Full crystallographic information is available from OCA.
Reference
Evolution of feedback-inhibited beta /alpha barrel isoenzymes by gene duplication and a single mutation., Hartmann M, Schneider TR, Pfeil A, Heinrich G, Lipscomb WN, Braus GH, Proc Natl Acad Sci U S A. 2003 Feb 4;100(3):862-7. Epub 2003 Jan 22. PMID:12540830
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