AmiE (Vapar_0135, C5CWZ4) is a 344-amino-acid cytoplasmic aliphatic amidase (EC 3.5.1.4) in Variovorax paradoxus S110 belonging to the carbon-nitrogen hydrolase superfamily (PF00795, HAMAP rule MF_01242). It catalyzes the hydrolysis of short-chain linear aliphatic amides to their corresponding monocarboxylate organic acids and ammonium using a conserved Glu59-Lys134-Cys166 catalytic triad, where Cys166 acts as the active-site nucleophile that forms a covalent acyl-enzyme thioester intermediate. In the rhizosphere, AmiE enables assimilation of environmental and plant-derived short-chain amides as nitrogen and carbon sources.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004040 amidase activity | IEA GO_REF:0000120 | ACCEPT | Summary: AmiE catalyzes the hydrolysis of short-chain aliphatic monocarboxylic acid amides to monocarboxylates and ammonium (EC 3.5.1.4). Reason: Supported by HAMAP rule MF_01242, InterPro family IPR023719, and the conserved Glu59-Lys134-Cys166 catalytic triad. Supporting Evidence: UniProtKB:C5CWZ4 CC -!- FUNCTION: Catalyzes the hydrolysis of short-chain aliphatic amides to CC their corresponding organic acids with release of ammonia. CC {ECO:0000255|HAMAP-Rule:MF_01242}. |
| GO:0016811 hydrolase activity, acting on carbon-nitrogen (but not peptide) bonds, in linear amides | IEA GO_REF:0000118 | TOO GENERAL | Summary: AmiE hydrolyzes non-peptide carbon-nitrogen bonds in linear amides. Reason: The parent term GO:0016811 is true of AmiE but subsumed by the more specific child term amidase activity (GO:0004040) already accepted on this record via HAMAP rule MF_01242. Supporting Evidence: UniProtKB:C5CWZ4 DR HAMAP; MF_01242; Aliphatic_amidase; 1. |
| GO:0005829 cytosol | IC UniProtKB:C5CWZ4 | NEW | Summary: AmiE is a soluble cytoplasmic enzyme lacking signal peptides or transmembrane segments. Reason: Inferred by curator (IC) because bacterial aliphatic amidases of the HAMAP MF_01242 family are soluble cytoplasmic enzymes lacking signal peptides or transmembrane helices. Supporting Evidence: UniProtKB:C5CWZ4 DR HAMAP; MF_01242; Aliphatic_amidase; 1. |
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Download this section (compressed HTML)Q: Does Variovorax paradoxus S110 AmiE (Vapar_0135) participate in an indole-3-acetamide (IAM) hydrolase auxiliary pathway or is its substrate range restricted to short-chain aliphatic amides such as acetamide and propionamide?
Experiment: Purify recombinant V. paradoxus S110 AmiE (Vapar_0135) and determine its steady-state kcat/Km profile across aliphatic amides (acetamide, propionamide, acrylamide) versus aromatic/arylacetamides (indole-3-acetamide, phenylacetamide).
Hypothesis: Consistent with canonical AmiE enzymes (IPR023719 / MF_01242), Vapar_0135 exhibits high catalytic efficiency toward C2-C4 aliphatic amides and sterically excludes bulky arylacetamides.
Type: In vitro steady-state enzyme kinetics
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