Heterologous expression of Melanocarpus albomyces cellobiohydrolase Cel7B, and random mutagenesis to improve its thermostability
| Autor: | Jari Vehmaanperä, Harry Boer, Markus Linder, Juha Rouvinen, Anu Koivula, Sanni Voutilainen, Terhi Puranen |
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| Jazyk: | angličtina |
| Rok vydání: | 2007 |
| Předmět: |
Random mutagenesis
Mutant High-throughput screening Bioengineering Cellulase Saccharomyces cerevisiae Biology Applied Microbiology and Biotechnology Biochemistry Yeast chemistry.chemical_compound Hydrolysis chemistry Hydrolase biology.protein Glycosyl Heterologous expression Thermostability Melanocarpus albomyces Biotechnology |
| Zdroj: | Voutilainen, S, Boer, H, Linder, M, Puranen, T, Rouvinen, J, Vehmaanperä, J & Koivula, A 2007, ' Heterologous expression of Melanocarpus albomyces cellobiohydrolase Cel7B, and random mutagenesis to improve its thermostability ', Enzyme and Microbial Technology, vol. 41, no. 3, pp. 234-243 . https://doi.org/10.1016/j.enzmictec.2007.01.015 |
| ISSN: | 1879-0909 0141-0229 |
| DOI: | 10.1016/j.enzmictec.2007.01.015 |
| Popis: | Fungal cellobiohydrolases from the glycosyl hydrolase family 7 are key enzymes in crystalline cellulose hydrolysis. Difficulties in heterologous expression in a bacterial or yeast host have hampered engineering of these cellulases for industrial application. We report here a successful expression of the single-module cellobiohydrolase Cel7B from a thermophilic fungus Melanocarpus albomyces in Saccharomyces cerevisiae (Sc Cel7B). An automated, robotic thermostability screening method, based on residual activity measurements on a small soluble substrate methylumbelliferyl-lactoside (MULac), was then set-up to screen the first generation random mutant libraries. Out of the nine positive thermostable mutants, we picked three based on structural considerations, each containing a single amino acid change (A30T, G184D or S290T). Cel7B A30T and S290T mutants showed improved unfolding temperature (Tm) by 1.5 and 3.5 °C, respectively.In addition, the temperature optimum (Topt) on a soluble substrate had improved by 5 °C for the A30T mutant. Interestingly, the best enzyme variant on microcrystalline cellulose (Avicel) hydrolysis was the Cel7B S290T, which could hydrolyse Avicel at 70 °C two times more effectively than the Sc Cel7B. Overall the consensus mutation S290T, located in the hydrophobic core of Cel7B, led to a cellobiohydrolase variant having also application potential in hydrolysis of polymeric substrates at elevated temperatures. |
| Databáze: | OpenAIRE |
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