P69910

EV
Gene name
gadB (b1493, JW1488)
Protein name
Glutamate decarboxylase beta
Names
GAD-beta
Species
Escherichia coli (strain K12)
KEGG Pathway
eco:b1493
EC number
4.1.1.15: Carboxy-lyases
Protein Class

Descriptions

GadB, or glutamate decarboxylase, is an enzyme in Escherichia coli that helps the bacteria survive stomach acidity by converting glutamate to γ-aminobutyrate (GABA), consuming protons in the process. The N-terminal 14 residues of GadB are crucial for its function. Their deletion results in loss of cooperativity and sensitivity to chloride, affecting the enzyme’s activation. GadB can switch between active and inactive forms. At higher pH levels, it autoinhibits by forming a novel structure of the cofactor pyridoxal 5′-phosphate (aldamine), which involves a covalent bond with the enzyme’s histidine residue, leading to inactivation. This mechanism is significant for maintaining pH balance within the cell. Chloride ions, abundant in gastric secretions, act as allosteric activators of GadB, enhancing its decarboxylase activity and aiding in acid resistance.

Autoinhibitory domains (AIDs)

1-14 (N-terminal autoinhibitory region) EV

Target domain

463-466 (C-terminal tail)

Relief mechanism

Ligand binding

Assay

Structural analysis, Deletion assay

Accessory elements

No accessory elements

References

Autoinhibited structure

Activated structure

9 structures for P69910

Entry ID Method Resolution Chain Position Source
1PMM X-ray 200 A A/B/C/D/E/F 1-466 PDB
1PMO X-ray 230 A A/B/C/D/E/F 1-466 PDB
2DGK X-ray 190 A A/B/C/D/E/F 15-466 PDB
2DGL X-ray 315 A A/B/C/D/E/F 1-466 PDB
2DGM X-ray 195 A A/B/C/D/E/F 1-466 PDB
3FZ6 X-ray 282 A A/B/C/D/E/F 1-466 PDB
3FZ7 X-ray 250 A A/B/C/D/E/F 1-466 PDB
3FZ8 X-ray 300 A A/B/C/D/E/F 1-466 PDB
AF-P69910-F1 Predicted AlphaFoldDB

No variants for P69910

Variant ID(s) Position Change Description Diseaes Association Provenance
No variants for P69910

No associated diseases with P69910

5 regional properties for P69910

Type Name Position InterPro Accession
domain Formin, FH3 domain 281 - 468 IPR010472
domain Formin, GTPase-binding domain 94 - 277 IPR010473
domain Diaphanous autoregulatory (DAD) domain 1037 - 1067 IPR014767
domain Rho GTPase-binding/formin homology 3 (GBD/FH3) domain 94 - 456 IPR014768
domain Formin, FH2 domain 616 - 1057 IPR015425

Functions

Description
EC Number 4.1.1.15 Carboxy-lyases
Subcellular Localization
  • Cytoplasm
  • Membrane
  • Localized exclusively in the cytoplasm at neutral pH, but is recruited to the membrane when the pH falls
PANTHER Family
PANTHER Subfamily
PANTHER Protein Class
PANTHER Pathway Category No pathway information available

2 GO annotations of cellular component

Name Definition
cytosol The part of the cytoplasm that does not contain organelles but which does contain other particulate matter, such as protein complexes.
membrane A lipid bilayer along with all the proteins and protein complexes embedded in it an attached to it.

2 GO annotations of molecular function

Name Definition
glutamate decarboxylase activity Catalysis of the reaction: L-glutamate = 4-aminobutanoate + CO2.
pyridoxal phosphate binding Binding to pyridoxal 5' phosphate, 3-hydroxy-5-(hydroxymethyl)-2-methyl4-pyridine carboxaldehyde 5' phosphate, the biologically active form of vitamin B6.

2 GO annotations of biological process

Name Definition
glutamate catabolic process The chemical reactions and pathways resulting in the breakdown of glutamate, the anion of 2-aminopentanedioic acid.
intracellular pH elevation Any process that increases the internal pH of a cell, measured by the concentration of the hydrogen ion.

6 homologous proteins in AiPD

UniProt AC Gene Name Protein Name Species Evidence Code
Q04792 GAD1 Glutamate decarboxylase Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast) PR
P69908 gadA Glutamate decarboxylase alpha Escherichia coli (strain K12) PR
Q9LSH2 GAD5 Glutamate decarboxylase 5 Arabidopsis thaliana (Mouse-ear cress) PR
Q9ZPS3 GAD4 Glutamate decarboxylase 4 Arabidopsis thaliana (Mouse-ear cress) PR
Q42521 GAD1 Glutamate decarboxylase 1 Arabidopsis thaliana (Mouse-ear cress) SS
P54767 Glutamate decarboxylase Solanum lycopersicum (Tomato) (Lycopersicon esculentum) PR
10 20 30 40 50 60
MDKKQVTDLR SELLDSRFGA KSISTIAESK RFPLHEMRDD VAFQIINDEL YLDGNARQNL
70 80 90 100 110 120
ATFCQTWDDE NVHKLMDLSI NKNWIDKEEY PQSAAIDLRC VNMVADLWHA PAPKNGQAVG
130 140 150 160 170 180
TNTIGSSEAC MLGGMAMKWR WRKRMEAAGK PTDKPNLVCG PVQICWHKFA RYWDVELREI
190 200 210 220 230 240
PMRPGQLFMD PKRMIEACDE NTIGVVPTFG VTYTGNYEFP QPLHDALDKF QADTGIDIDM
250 260 270 280 290 300
HIDAASGGFL APFVAPDIVW DFRLPRVKSI SASGHKFGLA PLGCGWVIWR DEEALPQELV
310 320 330 340 350 360
FNVDYLGGQI GTFAINFSRP AGQVIAQYYE FLRLGREGYT KVQNASYQVA AYLADEIAKL
370 380 390 400 410 420
GPYEFICTGR PDEGIPAVCF KLKDGEDPGY TLYDLSERLR LRGWQVPAFT LGGEATDIVV
430 440 450 460
MRIMCRRGFE MDFAELLLED YKASLKYLSD HPKLQGIAQQ NSFKHT