Ig-like Domain in Endoglucanase Cel9A from Alicyclobacillus acidocaldarius Makes Dependent the Enzyme Stability on Calcium
| Autor: | Alireza Tarinejad, Khosro Khajeh, Fatemeh Rashno, Mehrnaz Haghi, Fereshteh S. Younesi, Mohammad Pazhang, Faramarz Mehrnejad, Saeed Najavand |
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| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Alicyclobacillus chemistry.chemical_element Bioengineering Plasma protein binding Immunoglobulin domain Cellulase Calcium Applied Microbiology and Biotechnology Biochemistry Substrate Specificity 03 medical and health sciences Enzyme Stability Binding site Molecular Biology chemistry.chemical_classification Binding Sites 030102 biochemistry & molecular biology biology Hydrogen bond biology.organism_classification 030104 developmental biology Enzyme chemistry Biophysics biology.protein Immunoglobulin Domains Protein Binding Biotechnology |
| Zdroj: | Molecular Biotechnology. 60:698-711 |
| ISSN: | 1559-0305 1073-6085 |
| DOI: | 10.1007/s12033-018-0105-4 |
| Popis: | Endoglucanase Cel9A from Alicyclobacillus acidocaldarius (AaCel9A) has an Ig-like domain and the enzyme stability is dependent to calcium. In this study the effect of calcium on the structure and stability of the wild-type enzyme and the truncated form (the wild-type enzyme without Ig-like domain, AaCel9AΔN) was investigated. Fluorescence quenching results indicated that calcium increased and decreased the rigidity of the wild-type and truncated enzymes, respectively. RMSF results indicated that AaCel9A has two flexible regions (regions A and B) and deleting the Ig-like domain increased the truncated enzyme stability by decreasing the flexibility of region B probably through increasing the hydrogen bonds. Calcium contact map analysis showed that deleting the Ig-like domain decreased the calcium contacting residues and their calcium binding affinities, especially, in region B which has a role in calcium binding site in AaCel9A. Metal depletion and activity recovering as well as stability results showed that the structure and stability of the wild-type and truncated enzymes are completely dependent on and independent of calcium, respectively. Finally, one can conclude that the deletion of Ig-like domain makes AaCel9AΔN independent of calcium via decreasing the flexibility of region B through increasing the hydrogen bonds. This suggests a new role for the Ig-like domain which makes AaCel9A structure dependent on calcium. |
| Databáze: | OpenAIRE |
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