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Protein engineering of selected residues from conserved sequence regions of a novel Anoxybacillus α-amylase


Citation

Ranjani, Velayudhan and Janecek, Stefan and Chai, Kian Piaw and Shahir, Shafinaz and Raja Abdul Rahman, Raja Noor Zaliha and Chan, Kok Gan and Goh, Kian Mau (2014) Protein engineering of selected residues from conserved sequence regions of a novel Anoxybacillus α-amylase. Scientific Reports, 4. art. no. 5850. pp. 1-8. ISSN 2045-2322

Abstract

The α-amylases from Anoxybacillus species (ASKA and ADTA), Bacillus aquimaris (BaqA) and Geobacillus thermoleovorans (GTA, Pizzo and GtamyII) were proposed as a novel group of the α-amylase family GH13. An ASKA yielding a high percentage of maltose upon its reaction on starch was chosen as a model to study the residues responsible for the biochemical properties. Four residues from conserved sequence regions (CSRs) were thus selected, and the mutants F113V (CSR-I), Y187F and L189I (CSR-II) and A161D (CSR-V) were characterised. Few changes in the optimum reaction temperature and pH were observed for all mutants. Whereas the Y187F (t1/2 43 h) and L189I (t1/2 36 h) mutants had a lower thermostability at 65°C than the native ASKA (t1/2 48 h), the mutants F113V and A161D exhibited an improved t1/2 of 51 h and 53 h, respectively. Among the mutants, only the A161D had a specific activity, kcat and kcat/Km higher (1.23-, 1.17- and 2.88-times, respectively) than the values determined for the ASKA. The replacement of the Ala-161 in the CSR-V with an aspartic acid also caused a significant reduction in the ratio of maltose formed. This finding suggests the Ala-161 may contribute to the high maltose production of the ASKA.


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Additional Metadata

Item Type: Article
Divisions: Faculty of Biotechnology and Biomolecular Sciences
DOI Number: https://doi.org/10.1038/srep05850
Publisher: Nature Publishing Group
Keywords: Protein engineering; Conserved sequence regions; Novel Anoxybacillus α-amylase
Depositing User: Nurul Ainie Mokhtar
Date Deposited: 30 Dec 2015 10:41
Last Modified: 28 Sep 2016 07:09
Altmetrics: http://www.altmetric.com/details.php?domain=psasir.upm.edu.my&doi=10.1038/srep05850
URI: http://psasir.upm.edu.my/id/eprint/35093
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