A conformationally isoformic thermophilic protein with high kinetic unfolding barriers
| Autor: | Uno Carlsson, Ian A. Nicholls, Martin Karlsson, Rajesh Mishra, Linus Olofsson, Per Hammarström |
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| Rok vydání: | 2008 |
| Předmět: |
Models
Molecular Guanidinium chloride Protein Folding Prions Protein Conformation Protein Renaturation Kinetics Supramolecular chemistry Thermoanaerobacter Saccharomyces cerevisiae Cellular and Molecular Neuroscience chemistry.chemical_compound Urea Molecular Biology Guanidine Alcohol dehydrogenase Pharmacology biology Chemistry Thermophile Alcohol Dehydrogenase Cell Biology Isoenzymes Folding (chemistry) Crystallography Cross-Linking Reagents Models Chemical biological sciences biology.protein Unfolded protein response Thermodynamics Molecular Medicine Dimerization |
| Zdroj: | Cellular and Molecular Life Sciences. 65:827-839 |
| ISSN: | 1420-9071 1420-682X |
| Popis: | The basis for the stability of thermophilic proteins is of fundamental interest for extremophile biology. We investigated the folding and unfolding processes of the homotetrameric Thermoanaerobacter brockii alcohol dehydrogenase (TBADH). TBADH subunits were 4.8 kcal/mol less stable towards guanidinium chloride (GdmCl) unfolding compared to urea, indicating ionic modulation of TBADH stability. Strongly denaturing conditions promoted mono-exponential unfolding kinetics with linear dependence on denaturant concentration. Here TBADH unfolded >40-fold slower when extrapolated from urea as compared to GdmCl unfolding. A marked unfolding hysteresis was shown when comparing refolding and unfolding in urea. An unusual biphasic unfolding trajectory with an exceptionally slow phase at intermediate concentrations of GdmCl and urea was also observed. We advocate that TBADH forms two distinctly different tetrameric isoforms, and likely an ensemble of native states. This unusual supramolecular folding behavior has been shown responsible for formation of amyloidotic yeast prion strains and can have functional importance for TBADH. |
| Databáze: | OpenAIRE |
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