Tolan, Dean R. and Schuler, Benjamin and Beernink, Peter T. and Jaenicke, Rainer (2003) Thermodynamic analysis of the dissociation of the aldolase tetramer substituted at one or both of the subunit interfaces. BIOLOGICAL CHEMISTRY, 384 (10-11). pp. 1463-1471. ISSN 1431-6730, 1437-4315
Full text not available from this repository.Abstract
The fructose-1,6-bis(phosphate) alldolase isologous tetramer tightly associates through two different subunit interfaces defined by its 222 symmetry. Both single- and double-interfacial mutant aldolases have a destabilized quaternary structure, but there is little effect on the catalytic activity. These enzymes are however thermolabile. This study demonstrates the temperature-dependent dissociation of the mutant enzymes and determines the dissociation free energies of both mutant and native aldolase. Subunit dissociation is measured by sedimentation equilibrium in the analytical ultracentrifuge. At 25degreesC the tetramer-dimer dissociation constants for each single-mutant enzyme are similar, about 10(-6) m. For the double-mutant enzyme, sedimentation velocity experiments on sucrose density gradients support a tetramer-monomer equilibrium. Furthermore, sedimentation equilibrium experiments determined a dissociation constant of 10(-15) M-3 for the double-mutant enzyme. By the same methods the upper limit for the dissociation constant of wild-type aldolase A is approximately 10(-28) M-3, which indicates an extremely stable tetramer. The thermodynamic values describing monomer-tetramer and dimer-tetramer equilibria are analyzed with regard to possible cooperative interaction between the two subunit interfaces.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | RABBIT-MUSCLE ALDOLASE; FRUCTOSE DIPHOSPHATE ALDOLASE; MONOMERIC TRIOSEPHOSPHATE ISOMERASE; SITE-DIRECTED MUTAGENESIS; QUATERNARY STRUCTURE; GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE; BIFUNCTIONAL REAGENTS; BIOLOGICAL-SYSTEMS; MAGNESIUM CHLORIDE; ACID DISSOCIATION; analytical ultracentrifugation; dissociation constant; protein stability; quaternary structure; site-directed mutagenesis |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Biophysik und physikalische Biochemie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 28 Jul 2021 11:09 |
| Last Modified: | 28 Jul 2021 11:09 |
| URI: | https://pred.uni-regensburg.de/id/eprint/38536 |
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