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| [[Image:1hfb.gif|left|200px]] | | {{Seed}} |
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| {{STRUCTURE_1hfb| PDB=1hfb | SCENE= }} | | {{STRUCTURE_1hfb| PDB=1hfb | SCENE= }} |
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| '''CRYSTAL STRUCTURE OF THE TYROSINE-REGULATED 3-DEOXY-D-ARABINO-HEPTULOSONATE-7-PHOSPHATE SYNTHASE FROM SACCHAROMYCES CEREVISIAE COMPLEXED WITH PHOSPHOENOLPYRUVATE'''
| | ===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==
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| 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. | | The line below this paragraph, {{ABSTRACT_PUBMED_12540830}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 12540830 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_12540830}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Beta-alpha-barrel]] | | [[Category: Beta-alpha-barrel]] |
| [[Category: Lyase]] | | [[Category: Lyase]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 18:47:27 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 08:06:28 2008'' |
