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

Study Summary

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: SD of Tm ; Derived Quantity: t1/2 at 45 °C: Enhanced Fold ; Derived Quantity: △T15_50
Libraries Variants for GadB

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P
 

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)


Relevant PDB Entries

Structure ID Release Date Resolution Structure Title
1XEY 2004-09-13T00:00:00+0000 2.05 Crystal structure of the complex of Escherichia coli GADA with glutarate at 2.05 A resolution
1PMO 2003-06-11T00:00:00+0000 2.3 Crystal structure of Escherichia coli GadB (neutral pH)
2DGK 2006-03-14T00:00:00+0000 1.9 Crystal structure of an N-terminal deletion mutant of Escherichia coli GadB in an autoinhibited state (aldamine)
2DGM 2006-03-14T00:00:00+0000 1.95 Crystal structure of Escherichia coli GadB in complex with iodide
1PMM 2003-06-11T00:00:00+0000 2.0 Crystal structure of Escherichia coli GadB (low pH)
2DGL 2006-03-14T00:00:00+0000 3.15 Crystal structure of Escherichia coli GadB in complex with bromide
3FZ6 2009-01-23T00:00:00+0000 2.82 Crystal structure of glutamate decarboxylase beta from Escherichia coli: complex with xenon
3FZ7 2009-01-23T00:00:00+0000 2.5 Crystal structure of apo glutamate decarboxylase beta from Escherichia coli
3FZ8 2009-01-23T00:00:00+0000 3.0 Crystal structure of glutamate decarboxylase beta from Escherichia coli: reduced Schiff base with PLP

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
592.2 A,B,C,D,E,F Glutamate decarboxylase beta Q83PR1 DCEA_SHIFL
592.2 A,B,C,D,E,F Glutamate decarboxylase beta P58228 DCEA_ECO57
593.4 A,B,C,D,E,F Glutamate decarboxylase beta P69908 DCEA_ECOLI
593.4 A,B,C,D,E,F Glutamate decarboxylase beta P69909 DCEA_ECOL6
597.6 A,B,C,D,E,F Glutamate decarboxylase beta Q8FHG5 DCEB_ECOL6
600.0 A,B,C,D,E,F Glutamate decarboxylase beta P69912 DCEB_SHIFL
600.0 A,B,C,D,E,F Glutamate decarboxylase beta P69910 DCEB_ECOLI
600.0 A,B,C,D,E,F Glutamate decarboxylase beta P69911 DCEB_ECO57