Deletion combined with saturation mutagenesis of N-terminal residues in transglutaminase from Streptomyces hygroscopicus results in enhanced activity and thermostability

► The activity of transglutaminase could be enhanced by the N-terminal residues deletion. ► Deletion combined with saturation mutagenesis of N-terminal residues results in enhanced activity and thermostability. ► The amino acid (Asp) is very important for the thermostability of transglutaminase. Tra...

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Bibliographic Details
Published in:Process biochemistry (1991) 2012-12, Vol.47 (12), p.2329-2334
Main Authors: Chen, Kangkang, Liu, Song, Ma, Jianlong, Zhang, Dongxu, Shi, Zhongping, Du, Guocheng, Chen, Jian
Format: Article
Language:English
Subjects:
aspartic acid
circular dichroism spectroscopy
crosslinking
half life
melting point
mutagenesis
mutants
N-terminus
protein-glutamine gamma-glutamyltransferase
proteins
Saturation mutagenesis
Specific activity
Streptomyces hygroscopicus
thermal stability
Thermostability
Transglutaminase
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Summary:► The activity of transglutaminase could be enhanced by the N-terminal residues deletion. ► Deletion combined with saturation mutagenesis of N-terminal residues results in enhanced activity and thermostability. ► The amino acid (Asp) is very important for the thermostability of transglutaminase. Transglutaminase (TGase) is an important industrial enzyme that catalyzes the cross-linking of proteins. In this study, the N-terminal residues were deleted and substituted to improve the activity and thermostability of Streptomyces hygroscopicus TGase. Seven N-terminal residues of TGase were chosen to be deleted individually. The mutated TGase missing the first four residues showed an increase in specific activity of 32.92%. The fifth residue (E5) in the N-terminus was then selected for substitution with the 19 other amino acids. The mutant replacing the fifth residue with an aspartic acid exhibited a 1.85-fold higher specific activity and a 2.7-fold longer half-life at 50°C when compared with the wild-type enzyme. The melting temperature of the mutated TGase increased from 68.9 to 79.1°C by circular dichroism spectroscopy analysis. This study showed that substitution combined with deletion of the N-terminal amino acids could enhance the activity and thermostability of TGase.
ISSN:1359-5113
1873-3298
DOI:10.1016/j.procbio.2012.09.013