1kiz
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(New page: 200px<br /><applet load="1kiz" size="450" color="white" frame="true" align="right" spinBox="true" caption="1kiz, resolution 2.60Å" /> '''D100E trichodiene sy...)
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Revision as of 17:09, 20 November 2007
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D100E trichodiene synthase complexed with pyrophosphate
Overview
The 2.4 A resolution X-ray crystal structure of D100E trichodiene synthase, and the 2.6 A resolution structure of its complex with inorganic, pyrophosphate are reported. The D100E amino acid substitution in the, so-called "aspartate-rich" motif does not result in large changes to the, overall structure of the enzyme. In the pyrophosphate complex, however, pyrophosphate coordinates two Mg(2+) ions at the mouth of the active site, without causing large changes in the structure of the enzyme. This, contrasts with pyrophosphate binding in the wild-type enzyme, where, pyrophosphate coordinates three Mg(2+) ions and triggers a significant, conformational change that closes the mouth of the active site and, optimizes packing density in the enzyme-substrate complex. The attenuation, of active site closure in D100E trichodiene synthase compromises, enzyme-substrate packing density and confers additional spatial and, conformational degrees of freedom on the substrate and carbocation, intermediates, which in turn results in the formation of five alternate, sesquiterpene products in addition to trichodiene. By extension, then, the, diversity of terpene cyclases in biology may have evolved in part by amino, acid substitutions that fine-tune structural changes dependent on, metal-diphosphate complexation that govern the formation of the active, site template and enzyme-substrate packing density.
About this Structure
1KIZ is a Single protein structure of sequence from Fusarium sporotrichioides with MG, POP and EDO as ligands. Active as Trichodiene synthase, with EC number 4.2.3.6 Full crystallographic information is available from OCA.
Reference
X-ray crystal structures of D100E trichodiene synthase and its pyrophosphate complex reveal the basis for terpene product diversity., Rynkiewicz MJ, Cane DE, Christianson DW, Biochemistry. 2002 Feb 12;41(6):1732-41. PMID:11827517
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