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Enhancing the thermostability of α-glucosidase from Thermoanaerobacter tengcongensis MB4 by single proline substitution

Paper ID Volume ID Publish Year Pages File Format Full-Text
21234 43213 2010 6 PDF Available
Title
Enhancing the thermostability of α-glucosidase from Thermoanaerobacter tengcongensis MB4 by single proline substitution
Abstract

Thermostability can be increased by introducing prolines at suitable sites in target proteins. In this study, we compared five thermostable α-glucosidases and the moderate thermostable α-glucosidase (TtGluA) from Thermoanaerobacter tengcongensis MB4. Based on the amino acid sequence alignment, four sites (Leu152, Asn208, Lys285, and Thr430) of TtGluA were chosen for proline substitution to improve its thermostability. Thermostability of mutants L152P, K285P, and T430P increased evidently, but no thermostability improvement was observed for N208P. Compared to the wild-type enzyme, T5015 of T430P had a rise of 2 °C without distinct loss of activity. However, T5015 values of L152P and K285P increased 2 °C and 10.5 °C, respectively, while retaining activity of only 26.6% and 24.9% of wild-type enzyme. The Km of L152P, K285P, T430P and wild-type enzyme was 1.61, 0.32, 1.64, and 1.08 mM, respectively. These indicate that the selected sites are not only important for the thermostability but also related to the substrate binding and catalytic activity of TtGluA. The CD spectra analysis of the improved mutants and wild-type enzyme showed no distinct changes in their secondary structures. Combining analysis of secondary structure prediction and 3D structure modeling, the proline substitution at the three sites stabilized TtGluA possibly by reducing the flexibility of loop and random coil or (and) increasing the hydrophobic effect at these strategic regions with no evident structure change.

Keywords
α-Glucosidase; Thermoanaerobacter tengcongensis; Proline substitution; Thermostability improving; Structure modeling
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Enhancing the thermostability of α-glucosidase from Thermoanaerobacter tengcongensis MB4 by single proline substitution
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Bioscience and Bioengineering - Volume 110, Issue 1, July 2010, Pages 12–17
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us