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
ID: Bb3EiQLv
Submitter: Shu-Ching Ou
Submission Date: Dec. 28, 2018, 10:50 a.m.
Version: 1
Number of data points | 33 |
Proteins | Glutamate decarboxylase beta |
Unique complexes | 5 |
Assays/Quantities/Protocols | Experimental Assay: Tm ; Experimental Assay: Thermal-Inactivation Rate Constant at 45 °C ; Experimental Assay: t1/2 at 45 °C ; Experimental Assay: T15_50 ; Derived Quantity: SD of Tm ; Derived Quantity: t1/2 at 45 °C: Enhanced Fold ; Derived Quantity: △T15_50 |
Libraries | Variants for GadB |
Colors: | D | E | R | H | K | S | T | N | Q | A | V | I | L | M | F | Y | W | C | G | P |
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Percent Identity | Matching Chains | Protein | Accession | Entry Name |
---|---|---|---|---|
600.0 | A,B,C,D,E,F | Glutamate decarboxylase beta | P69911 | DCEB_ECO57 |
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 | P69912 | DCEB_SHIFL |
597.6 | A,B,C,D,E,F | Glutamate decarboxylase beta | Q8FHG5 | DCEB_ECOL6 |
593.4 | A,B,C,D,E,F | Glutamate decarboxylase beta | P69909 | DCEA_ECOL6 |
593.4 | A,B,C,D,E,F | Glutamate decarboxylase beta | P69908 | DCEA_ECOLI |
592.2 | A,B,C,D,E,F | Glutamate decarboxylase beta | P58228 | DCEA_ECO57 |
592.2 | A,B,C,D,E,F | Glutamate decarboxylase beta | Q83PR1 | DCEA_SHIFL |