Structure of trisodium D-2-phosphoglycerate hexahydrate

“…It appears that the PGA molecule is bound in a conformation different from that found in the crystals of the potassium salt of PGA. There, the plane of the carboxylic group is perpendicular to the plane of the three carbon atoms (Lis, 1985) while in the complex with enolase the electron density indicates a conformation with the carboxylic group and the C(2) and C(3) atoms approximately in one plane. Some distortion of substrate analogues bound to enolase in the presence of activating metal ions was observed before using absorption spectroscopy (Brewer & Collins, 1980).…”

Section: Resultsmentioning

confidence: 95%

“…The positions of the side chains in the environment of the substrate were refitted to omit difference Fourier maps. The dictionary for the PGA molecule was constructed by using the bond lengths and bond angles found in the crystal structure of trisodium 2-phospho-D-glycerate hexahydrate (Lis, 1985). The restraints were the same as for the protein model except that no restraints on the torsion angles of the substrate molecule were applied.…”

Section: Methodsmentioning

confidence: 99%

Mechanism of enolase: the crystal structure of enolase-magnesium-2-phosphoglycerate/phosphoenolpyruvate complex at 2.2-.ANG. resolution

Lebioda

Stec²

1991

Biochemistry

116

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Enolase in the presence of Mg2+ catalyzes the elimination of H2O from 2-phosphoglyceric acid (PGA) to form phosphoenolpyruvate (PEP) and the reverse reaction, the hydration of PEP to PGA. The structure of the ternary complex yeast enolase-Mg2(+)-PGA/PEP has been determined by X-ray diffraction and refined by crystallographic restrained least-squares to an R = 16.9% for those data with I/sigma (I) greater than or equal to 2 to 2.2-A resolution with a good geometry of the model. The structure indicates the substrate molecule in the active site has its hydroxyl group coordinated to the Mg2+ ion. The carboxylic group interacts with the side chains of His373 and Lys396. The phosphate group is H-bonded to the guanidinium group of Arg374. A water molecule H-bonded to the carboxylic groups of Glu168 and Glu211 is located at a 2.6-A distance from carbon-2 of the substrate in the direction of its proton. We propose that this cluster functions as the base abstracting the proton in the catalytic process. The proton is probably transferred, first to the water molecule, then to Glu168, and further to the substrate hydroxyl to form a water molecule. Some analogy is apparent between the initial stages of the enolase reverse reaction, the hydration of PEP, and the proteolytic mechanism of the metallohydrolases carboxypeptidase A and thermolysin. The substrate/product binding is accompanied by large movements of loops Ser36-His43 and Ser158-Gly162. The role of these conformational changes is not clear at this time.

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“…The shape of ligand electron densities remained essentially unchanged during refinement. The dictionary for the ligand molecules was constructed by using the bond lengths and bond angles found in the crystal structure of trisodium 2-phospho-oglycerate hexahydrate (Lis, 1985). No restraints on the torsion angles of the substrate molecule were applied.…”

Section: Methodsmentioning

confidence: 99%

Inhibition of enolase: the crystal structures of enolase-calcium(2+)-2-phosphoglycerate and enolase-zinc(2+)-phosphoglycolate complexes at 2.2-.ANG. resolution

Lebioda¹,

Stec²,

Brewer³

et al. 1991

Biochemistry

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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.

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Structure of trisodium D-2-phosphoglycerate hexahydrate

Cited by 7 publications

References 2 publications

Structure of silver(I) barium phosphoenolpyruvate trihydrate

Structure of silver(I) barium phosphoenolpyruvate trihydrate

Mechanism of enolase: the crystal structure of enolase-magnesium-2-phosphoglycerate/phosphoenolpyruvate complex at 2.2-.ANG. resolution

Inhibition of enolase: the crystal structures of enolase-calcium(2+)-2-phosphoglycerate and enolase-zinc(2+)-phosphoglycolate complexes at 2.2-.ANG. resolution

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