Rabbit Muscle Aldolase 20% glycerol, 300kV
Ontology highlight
ABSTRACT:
SUBMITTER: Benjamin Basanta
PROVIDER: EMPIAR-10867 | biostudies-other |
REPOSITORIES: biostudies-other
Similar Datasets
Project description: Not available
| EMPIAR-10866 | biostudies-other
Project description: Not available
| EMPIAR-10187 | biostudies-other
Project description:Rabbit muscle aldolase (RMA) was crystallized in complex with the low-complexity domain (LC4) of sorting nexin 9. Monoclinic crystals were obtained at room temperature that displayed large mosaicity and poor X-ray diffraction. However, orthorhombic RMA-LC4 crystals grown at 277 K under similar conditions exhibited low mosaicity, allowing data collection to 2.2 A Bragg spacing and structure determination. It was concluded that the improvement of crystal quality as indicated by the higher resolution of the new RMA-LC4 complex crystals was a consequence of the introduction of new lattice contacts at lower temperature. The lattice contacts corresponded to an increased number of interactions between high-entropy side chains that mitigate the lattice strain incurred upon cryocooling and accompanying mosaic spread increases. The thermodynamically unfavorable immobilization of high-entropy side chains used in lattice formation was compensated by an entropic increase in the bulk-solvent content owing to the greater solvent content of the crystal lattice.
| S-EPMC2864701 | biostudies-literature
Project description:Fructose-1,6-bisphosphate aldolase (aldolase) is an essential enzyme in glycolysis and gluconeogenesis. In addition to this primary function, aldolase is also known to bind to a variety of other proteins, a property that may allow it to perform 'moonlighting' roles in the cell. Although monomeric and dimeric aldolases possess full catalytic activity, the enzyme occurs as an unusually stable tetramer, suggesting a possible link between the oligomeric state and these noncatalytic cellular roles. Here, the first high-resolution X-ray crystal structure of rabbit muscle D128V aldolase, a dimeric form of aldolase mimicking the clinically important D128G mutation in humans associated with hemolytic anemia, is presented. The structure of the dimer was determined to 1.7 angstroms resolution with the product DHAP bound in the active site. The turnover of substrate to produce the product ligand demonstrates the retention of catalytic activity by the dimeric aldolase. The D128V mutation causes aldolase to lose intermolecular contacts with the neighboring subunit at one of the two interfaces of the tetramer. The tertiary structure of the dimer does not significantly differ from the structure of half of the tetramer. Analytical ultracentrifugation confirms the occurrence of the enzyme as a dimer in solution. The highly stable structure of aldolase with an independent active site is consistent with a model in which aldolase has evolved as a multimeric scaffold to perform other noncatalytic functions.
| S-EPMC2631105 | biostudies-literature
Project description: Not available
| EMPIAR-10215 | biostudies-other
Project description: Not available
| EMPIAR-10131 | biostudies-other
Project description:The interactions of the phosphorylated derivatives of hydroquinone (HQN-P2), resorcinol (RSN-P2), 4-hydroxybenzaldehyde (HBA-P) and 2, 4-dihydroxybenzaldehyde (DHBA-P; phosphate group at position 4) with fructose bisphosphate aldolase were analysed by enzyme kinetics, UV/visible difference spectroscopy and site-directed mutagenesis. Enzyme activity was competitively inhibited in the presence of HQN-P2, RSN-P2 and HBA-P, whereas DHBA-P exhibited slow-binding inhibition. Inhibition by DHBA-P involved active-site Schiff-base formation and required a phenol group ortho to the aldehyde moiety. Rates of enzyme inactivation and of Schiff-base formation by DHBA-P were identical, and corresponded to 3.2-3.5 DHBA-P molecules covalently bound per aldolase tetramer at maximal inactivation. Site-directed mutagenesis of the active-site lysine residues at positions 107, 146 and 229 was found to be consistent with Schiff-base formation between DHBA-P and Lys-146, and this was promoted by Lys-229. Mutation of Glu-187, located vicinally between Lys-146 and Lys-229 in the active site, perturbed the rate of Schiff-base formation, suggesting a functional role for Glu-187 in Schiff-base formation and stabilization. The decreased cleavage activity of the active-site mutants towards fructose 1, 6-bisphosphate is consistent with a proton-transfer mechanism involving Lys-229, Glu-187 and Lys-146.
| S-EPMC1218317 | biostudies-other
Project description: Not available
| EMPIAR-10130 | biostudies-other
Project description: Not available
| EMPIAR-10379 | biostudies-other
Project description:The method of competitive labelling with [(3)H]acetic anhydride as the labelling reagent was used to determine the properties of the active-centre lysine residue of rabbit muscle aldolase. This residue is much less reactive than a normal exposed lysine residue towards this reagent, and its reactive properties did not parallel the pH-activity profile for aldolase. At higher pH values it became reactive, but this was shown to be due to disruption of the enzyme structure. The binding of the competitive inhibitor phosphate did not alter the reactive properties. It is concluded that the active-centre lysine has an apparent pK(a) greater than 11.5 and probably is made nucleophilic during the catalytic process, perhaps by proton abstraction.
| S-EPMC1166103 | biostudies-other