1r53: Difference between revisions
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New page: left|200px<br /><applet load="1r53" size="450" color="white" frame="true" align="right" spinBox="true" caption="1r53, resolution 2.20Å" /> '''Crystal structure of... |
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[[Image:1r53.jpg|left|200px]]<br /><applet load="1r53" size=" | [[Image:1r53.jpg|left|200px]]<br /><applet load="1r53" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1r53, resolution 2.20Å" /> | caption="1r53, resolution 2.20Å" /> | ||
'''Crystal structure of the bifunctional chorismate synthase from Saccharomyces cerevisiae'''<br /> | '''Crystal structure of the bifunctional chorismate synthase from Saccharomyces cerevisiae'''<br /> | ||
==Overview== | ==Overview== | ||
Chorismate synthase (EC 4.2.3.5), the seventh enzyme in the shikimate | Chorismate synthase (EC 4.2.3.5), the seventh enzyme in the shikimate pathway, catalyzes the transformation of 5-enolpyruvylshikimate 3-phosphate (EPSP) to chorismate, which is the last common precursor in the biosynthesis of numerous aromatic compounds in bacteria, fungi, and plants. The chorismate synthase reaction involves a 1,4-trans-elimination of phosphoric acid from EPSP and has an absolute requirement for reduced FMN as a cofactor. We have determined the three-dimensional x-ray structure of the yeast chorismate synthase from selenomethionine-labeled crystals at 2.2-A resolution. The structure shows a novel betaalphabetaalpha fold consisting of an alternate tight packing of two alpha-helical and two beta-sheet layers, showing no resemblance to any documented protein structure. The molecule is arranged as a tight tetramer with D2 symmetry, in accordance with its quaternary structure in solution. Electron density is missing for 23% of the amino acids, spread over sequence regions that in the three-dimensional structure converge on the surface of the protein. Many totally conserved residues are contained within these regions, and they probably form a structured but mobile domain that closes over a cleft upon substrate binding and catalysis. This hypothesis is supported by previously published spectroscopic measurements implying that the enzyme undergoes considerable structural changes upon binding of both FMN and EPSP. | ||
==About this Structure== | ==About this Structure== | ||
1R53 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae]. Active as [http://en.wikipedia.org/wiki/Chorismate_synthase Chorismate synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.3.5 4.2.3.5] Full crystallographic information is available from [http:// | 1R53 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae]. Active as [http://en.wikipedia.org/wiki/Chorismate_synthase Chorismate synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.3.5 4.2.3.5] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1R53 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Quevillon-Cheruel, S.]] | [[Category: Quevillon-Cheruel, S.]] | ||
[[Category: Sorel, I.]] | [[Category: Sorel, I.]] | ||
[[Category: Tilbeurgh, H | [[Category: Tilbeurgh, H van.]] | ||
[[Category: two layers alpha-beta]] | [[Category: two layers alpha-beta]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:47:08 2008'' | ||
