5enl
From Proteopedia
OCA (Talk | contribs)
(New page: 200px<br /><applet load="5enl" size="450" color="white" frame="true" align="right" spinBox="true" caption="5enl, resolution 2.2Å" /> '''INHIBITION OF ENOLASE...)
Next diff →
Revision as of 17:22, 20 November 2007
|
INHIBITION OF ENOLASE: THE CRYSTAL STRUCTURES OF ENOLASE-CA2+-PHOSPHOGLYCERATE AND ENOLASE-ZN2+-PHOSPHOGLYCOLATE COMPLEXES AT 2.2-ANGSTROMS RESOLUTION
Overview
Enolase is a metalloenzyme which catalyzes the elimination of H2O from, 2-phosphoglyceric acid (PGA) to form phosphoenolpyruvate (PEP). Mg2+ and, Zn2+ are cofactors which strongly bind and activate the enzyme. Ca2+ also, binds strongly but does not produce activity. Phosphoglycolate (PG) is a, competitive inhibitor of enolase. The structures of two inhibitory ternary, complexes: yeast enolase-Ca2(+)-PGA and yeast enolase-Zn2(+)-PG, were, determined by X-ray diffraction to 2.2-A resolution and were refined by, crystallographic least-squares to R = 14.8% and 15.7%, respectively, with, good geometries of the models. These structures are compared with the, structure of the precatalytic ternary complex enolase-Mg2(+)-PGA/PEP, (Lebioda & Stec, 1991). In the complex enolase-Ca2(+)-PGA, the PGA, molecule coordinates to the Ca2+ ion with the hydroxyl group, as in the, precatalytic complex. The conformation of the PGA molecule is however, different. In the active complex, the organic part of the PGA molecule is, planar, similar to the product. In the inhibitory complex, the carboxylic, group is in an orthonormal conformation. In the inhibitory complex, enolase-Zn2(+)-PG, the PG molecule coordinates with the carboxylic group, in a monodentate mode. In both inhibitory complexes, the conformational, changes in flexible loops, which were observed in the precatalytic, complex, do not take place. The lack of catalytic metal ion binding, suggests that these conformational changes are necessary for the formation, of the catalytic metal ion binding site.
About this Structure
5ENL is a Single protein structure of sequence from Saccharomyces cerevisiae with CA and 2PG as ligands. Active as Phosphopyruvate hydratase, with EC number 4.2.1.11 Full crystallographic information is available from OCA.
Reference
Inhibition of enolase: the crystal structures of enolase-Ca2(+)- 2-phosphoglycerate and enolase-Zn2(+)-phosphoglycolate complexes at 2.2-A resolution., Lebioda L, Stec B, Brewer JM, Tykarska E, Biochemistry. 1991 Mar 19;30(11):2823-7. PMID:2007121
Page seeded by OCA on Tue Nov 20 19:29:55 2007
