Bile salt hydrolase, the member of Ntn-hydrolase family: Differential modes of structural and functional transitions during denaturation
| Autor: | R. Suresh Kumar, Cheravakkattu G. Suresh, James A. Brannigan, Guy Dodson, Sushama M. Gaikwad |
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| Rok vydání: | 2007 |
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Molecular Protein Denaturation Protein Folding Circular dichroism Bifidobacterium longum Clinical Biochemistry Biochemistry Protein Structure Secondary Amidohydrolases Enzyme Stability Genetics Molecular Biology Protein secondary structure Guanidine chemistry.chemical_classification biology Active site Cell Biology Hydrogen-Ion Concentration biology.organism_classification Protein tertiary structure Molten globule Enzyme assay Protein Structure Tertiary Enzyme chemistry biology.protein Bifidobacterium |
| Zdroj: | IUBMB Life. 59:118-125 |
| ISSN: | 1521-6543 |
| Popis: | Conformational transitions and functional stability of the bile salt hydrolase (BSH; cholylglycine EC: 3.5.1.24) from Bifidobacterium longum (BlBSH) cloned and expressed in E. coli were studied under thermal, chemical and pH-mediated denaturation conditions using fluorescence and CD spectroscopy. Thermal and Gdn-HCl-mediated denaturation of BlBSH is a multistep process of inactivation and unfolding. The inactivation and unfolding of the enzyme was found to be irreversible. Enzyme activity seems sensitive to even minor conformational changes at the active site. Thermal denaturation as such did not result in any insoluble protein aggregates. However, on treating with 0.25 - 1 M Gdn-HCl the enzyme showed increasing aggregation at temperatures of 40 - 55°C indicating more complex structural changes taking place in the presence of chemical denaturants. The enzyme secondary structure was still intact at acidic pH (pH 1 - 3). The perturbation in the tertiary structure at the acidic pH was detected through freshly formed solvent exposed hydrophobic patches on the enzyme. These changes could be due to the formation of an acid-induced molten globule-like state. IUBMB Life, 59: 118-125, 2007 |
| Databáze: | OpenAIRE |
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