1kiz
From Proteopedia
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. 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 Page seeded by OCA on Fri May 2 22:48:15 2008
