Increasing thermal stability of glutamate decarboxylase from Escherichia. coli by site-directed saturation mutagenesis and its application in GABA production.

Abstract

Gamma-amino butyric acid (GABA) is an important bio-product used in pharmaceuticals, functional foods, and a precursor of the biodegradable plastic polyamide 4 (Nylon 4). Glutamate decarboxylase B (GadB) from Escherichia. coli is a highly active biocatalyst that can convert l-glutamate to GABA. However, its practical application is limited by the poor thermostability and only active under acidic conditions of GadB. In this study, we performed site-directed saturation mutagenesis of the N-terminal residues of GadB from Escherichia coli to improve its thermostability. A triple mutant (M6, Gln5Ile/Val6Asp/Thr7Gln) showed higher thermostability, with a 5.6 times (560%) increase in half-life value at 45 °C, 8.7 °C rise in melting temperature (Tm) and a 14.3 °C rise in the temperature at which 50% of the initial activity remained after 15 min incubation (T

Submission Details

ID: Bb3EiQLv

Submitter: Shu-Ching Ou

Submission Date: Dec. 28, 2018, 10:50 a.m.

Version: 1

Publication Details
Fan LQ;Li MW;Qiu YJ;Chen QM;Jiang SJ;Shang YJ;Zhao LM,J Biotechnol (2018) Increasing thermal stability of glutamate decarboxylase from Escherichia. coli by site-directed saturation mutagenesis and its application in GABA production. PMID:29660473
Additional Information

Number of data points 33
Proteins Glutamate decarboxylase beta
Unique complexes 5
Assays/Quantities/Protocols Experimental Assay: T15_50 ; Experimental Assay: t1/2 at 45 °C ; Experimental Assay: Thermal-Inactivation Rate Constant at 45 °C ; Experimental Assay: Tm ; Derived Quantity: △T15_50 ; Derived Quantity: t1/2 at 45 °C: Enhanced Fold ; Derived Quantity: SD of Tm
Libraries Variants for GadB
Sequence Assay Result Units