GltA is a soluble cytoplasmic citrate synthase (EC 2.3.3.16) that condenses oxaloacetate and acetyl-CoA to citrate at the entry step of the tricarboxylic acid cycle in Pseudomonas putida KT2440. It belongs to the large bacterial, Gram-negative Type II citrate synthase class whose characterized members are hexameric and NADH-regulated, and it controls a central acetyl-CoA branch point between oxidative TCA-cycle flux and acetyl-CoA-dependent biosynthesis.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005737 cytoplasm | IEA GO_REF:0000120 | ACCEPT | Summary: Correct cytoplasmic localization for soluble bacterial citrate synthase. Reason: The soluble citrate-synthase family assignment and the central-metabolism role summarized in the OpenScientist report are consistent with cytoplasmic localization. Supporting Evidence: file:PSEPK/gltA/gltA-uniprot.txt CC -!- SIMILARITY: Belongs to the citrate synthase family. file:PSEPK/gltA/gltA-deep-research-openscientist.md Functionally, GltA operates in the **cytoplasm** and serves as the **gatekeeper of the acetyl-CoA node** |
| GO:0006099 tricarboxylic acid cycle | IEA GO_REF:0000120 | ACCEPT | Summary: Correct TCA-cycle annotation for the citrate synthase entry reaction. Reason: UniProt assigns Q88FA4 to the TCA cycle and records the oxaloacetate-plus-acetyl-CoA citrate synthase reaction that produces citrate at the TCA-cycle entry step. Supporting Evidence: file:PSEPK/gltA/gltA-uniprot.txt from oxaloacetate: step 1/2. file:PSEPK/gltA/gltA-uniprot.txt Reaction=oxaloacetate + acetyl-CoA + H2O = citrate + CoA + H(+); PMID:34343699 gltA, encoding citrate synthase |
| GO:0036440 citrate synthase activity | IEA GO_REF:0000120 | ACCEPT | Summary: Correct exact molecular function for GltA. Reason: Core molecular function. UniProt records the exact citrate synthase reaction and EC 2.3.3.16 for Q88FA4, and the organism-specific CRISPRi study identifies gltA as encoding citrate synthase; the OpenScientist report notes that kinetic constants have not been measured directly for this P. putida enzyme. Supporting Evidence: file:PSEPK/gltA/gltA-uniprot.txt EC=2.3.3.16; file:PSEPK/gltA/gltA-uniprot.txt Reaction=oxaloacetate + acetyl-CoA + H2O = citrate + CoA + H(+); PMID:34343699 gltA, encoding citrate synthase |
| GO:0046912 acyltransferase activity, acyl groups converted into alkyl on transfer | IEA GO_REF:0000002 | MARK AS OVER ANNOTATED | Summary: Correct but broad parent of the exact citrate synthase activity. Reason: This term is a less-specific ancestor of GO:0036440 citrate synthase activity, which is already annotated and captures the Q88FA4 reaction precisely. Supporting Evidence: file:PSEPK/gltA/gltA-uniprot.txt Reaction=oxaloacetate + acetyl-CoA + H2O = citrate + CoA + H(+); |
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Download this section (compressed HTML)Q: Has KT2440 GltA been purified directly, and do its kinetic constants and NADH inhibition match those inferred from E. coli and Pseudomonas homologs?
Experiment: Purify Q88FA4 and measure oxaloacetate and acetyl-CoA kinetic constants plus NADH inhibition to confirm the transferred NADH-regulated Type II citrate synthase parameters in the KT2440 enzyme.
Type: kinetic enzyme assay
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