Pappenberger, Günter and Schurig, Hartmut and Jaenicke, Rainer (1997) Disruption of an ionic network leads to accelerated thermal denaturation of D-glyceraldehyde-3-phosphate dehydrogenase from the hyperthermophilic bacterium Thermotoga maritima. JOURNAL OF MOLECULAR BIOLOGY, 274 (4). pp. 676-683. ISSN 0022-2836, 1089-8638
Full text not available from this repository.Abstract
The role of an ionic network; of four charged amino acid side-chains in the thermostability of the enzyme D-glyceraldehyde-3-phosphate dehydrogenase from the hyperthermophilic bacterium Thermotoga maritima (TmGAPDH) has been assessed by site-direct-ed mutagenesis, replacing the central residue of the ionic network, arginine 20, by either alanine (R20A) or asparagine (R20N). The purified mutant enzymes display no differences to the wild-type enzyme regarding spectroscopic properties and enzymatic activity. However, denaturation kinetics reveal that the resistance towards thermal denaturation is strongly diminished in the mutant enzymes. This is reflected by a decrease in free energy of activation for thermal unfolding of about 4 kJ/mol at 100 degrees C and a shift of temperature of half denaturation after one hour incubation from 96 to 89 degrees C for both mutant enzymes. Due to a large decrease in activation enthalpy, the effects of the mutations are temperature dependent and became even more significant at the physiological temperature of Thermotoga maritima (approximate to 80 degrees C). The importance of the arginine 20 side-chain for kinetic thermal stability is plausible in the light of its key role in the ionic network and tl-ie strategic positioning of this ionic network in the context of die overall protein structure. (C) 1997 Academic Press Limited.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SURFACE SALT BRIDGES; CRYSTAL-STRUCTURE; PROTEIN STABILITY; SULFOLOBUS-SOLFATARICUS; DIRECTED MUTAGENESIS; PYROCOCCUS-FURIOSUS; RECOMBINANT ENZYME; ESCHERICHIA-COLI; HEAT-STABILITY; DETERMINANTS; electrostatic interaction; GAPDH; kinetic thermal stability; protein stability; site-directed mutagenesis |
| Subjects: | 500 Science > 540 Chemistry & allied sciences 500 Science > 570 Life sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Biophysik und physikalische Biochemie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 28 Mar 2023 05:09 |
| Last Modified: | 28 Mar 2023 05:09 |
| URI: | https://pred.uni-regensburg.de/id/eprint/50335 |
Actions (login required)
 |
View Item |
