1nel

From Proteopedia

Revision as of 20:04, 20 November 2007

FLUORIDE INHIBITION OF YEAST ENOLASE: CRYSTAL STRUCTURE OF THE ENOLASE-MG2+-F--PI COMPLEX AT 2.6-ANGSTROMS RESOLUTION

Overview

Enolase in the presence of its physiological cofactor Mg2+ is inhibited by, fluoride and phosphate ions in a strongly cooperative manner (Nowak, T, Maurer, P. Biochemistry 20:6901, 1981). The structure of the quaternary, complex yeast enolase-Mg(2+)-F(-)-Pi has been determined by X-ray, diffraction and refined to an R = 16.9% for those data with F/sigma (F) >, or = 3 to 2.6 A resolution with a good geometry of the model. The movable, loops of Pro-35-Ala-45, Val-153-Phe-169, and Asp-255-Asn-266 are in the, closed conformation found previously in the precatalytic substrate-enzyme, complex. Calculations of molecular electrostatic potential show that this, conformation stabilizes binding of negatively charged ligands at the Mg2+, ion more strongly than the open conformation observed in the native, enolase. This closed conformation is complementary to the transition, state, which also has a negatively charged ion, hydroxide, at Mg2+. The, synergism of inhibition by F- and Pi most probably is due to the, requirement of Pi for the closed conformation. It is possible that other, Mg(2+)-dependent enzymes that have OH- ions bound to the metal ion in the, transition state also will be inhibited by fluoride ions.

About this Structure

1NEL is a Single protein structure of sequence from Saccharomyces cerevisiae with MG, PO4 and F as ligands. Active as Phosphopyruvate hydratase, with EC number 4.2.1.11 Full crystallographic information is available from OCA.

Reference

Fluoride inhibition of yeast enolase: crystal structure of the enolase-Mg(2+)-F(-)-Pi complex at 2.6 A resolution., Lebioda L, Zhang E, Lewinski K, Brewer JM, Proteins. 1993 Jul;16(3):219-25. PMID:8346189

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