GH3.12 Antibody
Description
Biochemical Function of GH3.12
GH3.12 catalyzes the conjugation of amino acids to 4-hydroxybenzoic acid (4-HBA), a precursor in SA biosynthesis. Its enzymatic activity involves two steps:
-
Adenylation: Activation of 4-HBA via ATP-dependent adenylation.
-
Amino acid conjugation: Transfer of the adenylated 4-HBA to glutamate, forming 4-HBA-glutamate (4-HBA-Glu) .
Key kinetic properties (Table 1):
| Substrate | (μM) | (min⁻¹) | (μM⁻¹·min⁻¹) |
|---|---|---|---|
| 4-HBA | 37 ± 5 | 0.68 ± 0.03 | 0.018 |
| Benzoate | 7 ± 1 | 0.24 ± 0.01 | 0.034 |
| Glutamate | 460 ± 90 | 0.62 ± 0.06 | 0.0013 |
GH3.12 exhibits substrate specificity for small aromatic acids like 4-HBA and benzoate, with glutamate as the preferred amino acid .
Role in Salicylic Acid (SA) Biosynthesis and Plant Immunity
SA is a phytohormone essential for systemic acquired resistance (SAR). GH3.12 facilitates SA accumulation by:
-
Producing 4-HBA-Glu, a proposed intermediate in SA biosynthesis.
-
Regulating SA-dependent gene expression during pathogen attacks (e.g., Pseudomonas syringae) .
Mutant studies:
-
Arabidopsis gh3.12/pbs3 mutants show 50–70% reduced SA levels and impaired pathogen resistance.
-
Complementation with wild-type GH3.12 restores SA accumulation and defense responses .
Comparative Analysis of GH3 Enzymes
GH3 enzymes are classified into three subfamilies based on substrate preference:
| Subfamily | Substrates | Example Enzyme |
|---|---|---|
| I | Auxins (e.g., IAA) | AtGH3.1 |
| II | Jasmonates | AtGH3.11 |
| III | Benzoates/4-HBA | AtGH3.12 |
GH3.12 is the only subfamily III member in Arabidopsis, highlighting its unique role in SA metabolism .
Research Applications of GHAntibodies
While the provided sources focus on GH3.12’s enzymatic role, antibodies against GH3.12 are critical for:
-
Localization studies: Tracking GH3.12 expression in plant tissues during immune responses.
-
Functional assays: Validating enzyme activity in mutant complementation experiments.
-
Protein interaction studies: Identifying binding partners in SA signaling pathways.
Implications for Agricultural Biotechnology
-
Crop engineering: Overexpression of GH3.12 in crops could enhance disease resistance.
-
Pathogen resistance: Targeting GH3.12 activity may reduce reliance on chemical pesticides.
Product Specs
Constituents: 50% Glycerol, 0.01M PBS, pH 7.4
Target Background
- The X-ray crystal structure of GH3.12 has been elucidated in its closed conformation in complex with the non-hydrolysable ATP analogue AMPCPP and the substrate salicylate. PMID: 24100325
- WIN3 has been identified as a novel node within the salicylic acid signaling networks, regulating both plant defense and flowering time. PMID: 21543726
- Amino acid conjugation has been shown to be crucial in salicylic acid (SA) metabolism and induced defense responses, with PBS3 acting upstream of SA, directly on SA, or on a competitive inhibitor of SA. PMID: 17468220
- Molecular characterization of the GH3-LIKE DEFENSE GENE 1 (GDG1), a member of the GH3-like gene family, has revealed its importance in salicylic acid-mediated defense against the bacterial pathogen P. syringae. PMID: 17521413
- WIN3 (At5g13320) has been established as a key component of the RPS2 defense response pathway and a crucial factor in both basal and systemic defense. PMID: 17918621
- WIN3 is partially required for disease resistance induced by Pseudomonas syringae HopW1-1. PMID: 18266921
- Arabidopsis GH3.12 (PBS3) has been demonstrated to conjugate amino acids to 4-substituted benzoates and is inhibited by salicylate. PMID: 19189963
