FabV (PA2950) is the triclosan-resistant enoyl-[acyl-carrier-protein] reductase of Pseudomonas aeruginosa, a member of the TER/FabV family unrelated in sequence to FabI. It catalyses the NADH-dependent reduction of trans-2-enoyl-ACP to acyl-ACP, the last step of each elongation cycle of type II fatty acid synthesis, acting on enoyl-ACPs from C4 to C16; it also reduces crotonyl-CoA, but much more slowly. P. aeruginosa has a second, triclosan-sensitive enoyl-ACP reductase (FabI), and FabV is the main one: its deletion lowers enoyl-ACP reductase activity in cell extracts, slows growth, shifts the membrane towards unsaturated fatty acids, and makes the bacterium more than 2000-fold more sensitive to triclosan. Through its supply of acyl-ACPs, loss of FabV also reduces acyl-homoserine lactone quorum-sensing signal production, swarming and virulence-factor output.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004318 enoyl-[acyl-carrier-protein] reductase (NADH) activity | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from PTN002206122 (FabV clade; 3 seeds, 7 leaf IBAs in 6 taxa). Seeds are V. cholerae FabV (Q9KRA3, IDA PMID:18032386), Y. pestis FabV (Q8Z9U1, IDA PMID:22244758) and P. aeruginosa FabV itself (UniProt IDA PMID:19933806; PseudoCAP IMP PMID:27965638). Reason: The node term suits a FabV clade; all three seeds have purified-enzyme evidence, so the IBD stands without the PseudoCAP row. FabV among its own sources reflects its own IDA. Supporting Evidence: PMID:19933806 The addition of PaFabV, PaFabI, or EcFabI plus NADH to the reaction mixture yielded butyryl-ACP |
| GO:0004318 enoyl-[acyl-carrier-protein] reductase (NADH) activity | IDA PMID:19933806 Triclosan resistance of Pseudomonas aeruginosa PAO1 is due t... | ACCEPT | Summary: UniProt IDA; purified P. aeruginosa FabV reduces enoyl-ACPs with NADH. Reason: Direct activity assay on the purified enzyme, with kinetics on trans-2-decenoyl-ACP. Supporting Evidence: PMID:19933806 The addition of PaFabV, PaFabI, or EcFabI plus NADH to the reaction mixture yielded butyryl-ACP |
| GO:0004318 enoyl-[acyl-carrier-protein] reductase (NADH) activity | IEA GO_REF:0000120 | ACCEPT | Summary: UniRule/EC 1.3.1.9 mapping. Reason: Agrees with the purified-enzyme evidence. Supporting Evidence: file:PSEAE/fabV/fabV-uniprot.txt HAMAP; MF_01838; FabV_reductase; 1. |
| GO:0004318 enoyl-[acyl-carrier-protein] reductase (NADH) activity | IMP PMID:27965638 Functional Characterization of Triclosan-Resistant Enoyl-acy... | ACCEPT | Summary: PseudoCAP IMP, a PTN002206122 seed row. Enoyl-ACP reductase activity in cell-free extracts of the fabV deletion strain fell to about a third of wild type and rose on complementation. Reason: Full text read. Loss of activity in a mutant lysate would alone be weak evidence for the gene's own activity, but here the activity lost is exactly the one shown for the purified enzyme (PMID:19933806), the residual activity is explained by FabI, and complementation restores activity. The term is correct for FabV; seed verdict SOUND. Supporting Evidence: PMID:27965638 The ENR activity (in ΞΌmol/min per mg extract protein) in cell-free extract of PAO170 was 0.175 Β± 0.006, and was lower than that in the cell-free extract of wild-type strain PAO1 (0.478 Β± 0.032). |
| GO:0006633 fatty acid biosynthetic process | IBA GO_REF:0000033 | ACCEPT | Summary: IBA fatty acid biosynthetic process from the FabV clade. Reason: FabV performs the enoyl reduction step of each FAS II elongation cycle; the fabV mutant has a reduced fatty acid synthetic rate. Supporting Evidence: file:PSEAE/fabV/fabV-uniprot.txt Involved in the final reduction of the elongation cycle of fatty acid synthesis (FAS II). |
| GO:0006633 fatty acid biosynthetic process | IDA PMID:19933806 Triclosan resistance of Pseudomonas aeruginosa PAO1 is due t... | ACCEPT | Summary: UniProt IDA; FabV reconstitutes the enoyl reduction step of fatty acid synthesis in vitro. Reason: Core process; FabV catalyses a step of it. Supporting Evidence: PMID:19933806 The addition of PaFabV, PaFabI, or EcFabI plus NADH to the reaction mixture yielded butyryl-ACP |
| GO:0006633 fatty acid biosynthetic process | IEA GO_REF:0000120 | ACCEPT | Summary: UniRule/UniPathway mapping. Reason: Consistent with the experimental evidence. Supporting Evidence: file:PSEAE/fabV/fabV-uniprot.txt Involved in the final reduction of the elongation cycle of fatty acid synthesis (FAS II). |
| GO:0016491 oxidoreductase activity | IEA GO_REF:0000002 | TOO GENERAL | Summary: InterPro2GO oxidoreductase activity from the trans-2-enoyl-CoA reductase signature. Reason: True but entailed by GO:0004318 enoyl-[acyl-carrier-protein] reductase (NADH) activity, which this review accepts as the core function. Supporting Evidence: file:PSEAE/fabV/fabV-uniprot.txt InterPro; IPR010758; Trans-2-enoyl-CoA_reductase. |
| GO:0050343 trans-2-enoyl-CoA reductase (NADH) activity | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: IBA trans-2-enoyl-CoA reductase (NADH) from V. cholerae FabV and P. aeruginosa FabV. Reason: Purified FabV reduces crotonyl-CoA, a genuine secondary activity shared with the TER family, but its Vmax with crotonyl-CoA is about 30-fold lower than with trans-2-decenoyl-ACP, and the physiological substrate is enoyl-ACP. Supporting Evidence: file:PSEAE/fabV/fabV-uniprot.txt Vmax=7.9 nmol/min/mg enzyme for reductase activity with crotonyl-CoA |
| GO:0050343 trans-2-enoyl-CoA reductase (NADH) activity | IDA PMID:19933806 Triclosan resistance of Pseudomonas aeruginosa PAO1 is due t... | KEEP AS NON CORE | Summary: UniProt IDA; purified FabV reduces crotonyl-CoA with NADH. Reason: Real but secondary activity (see the IBA row). Supporting Evidence: PMID:19933806 The experimentally observed maximal velocities of FabV with crotonyl-CoA and trans -2-decenoyl-ACP were higher than the maximal velocities of FabI with the same substrates |
| GO:0050343 trans-2-enoyl-CoA reductase (NADH) activity | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: EC 1.3.1.44 mapping. Reason: Consistent with the IDA row; secondary activity. Supporting Evidence: file:PSEAE/fabV/fabV-uniprot.txt Vmax=7.9 nmol/min/mg enzyme for reductase activity with crotonyl-CoA |
| GO:0051287 NAD binding | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: IBA NAD binding from the FabV clade. Reason: FabV uses NADH as its reductant, so NAD binding is true; it is the cofactor of the core reductase activity rather than a function in its own right. Supporting Evidence: PMID:19933806 The addition of PaFabV, PaFabI, or EcFabI plus NADH to the reaction mixture yielded butyryl-ACP |
| GO:0051287 NAD binding | IDA PMID:19933806 Triclosan resistance of Pseudomonas aeruginosa PAO1 is due t... | KEEP AS NON CORE | Summary: UniProt IDA NAD binding (NADH-dependent activity). Reason: Cofactor binding underlying the core activity. Supporting Evidence: PMID:19933806 The addition of PaFabV, PaFabI, or EcFabI plus NADH to the reaction mixture yielded butyryl-ACP |
| GO:0051287 NAD binding | IEA GO_REF:0000104 | KEEP AS NON CORE | Summary: UniRule mapping. Reason: As for the IBA and IDA rows. Supporting Evidence: file:PSEAE/fabV/fabV-uniprot.txt Pfam; PF12242; Eno-Rase_NADH_b; 1. |
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Download this section (compressed HTML)Q: How are enoyl-ACP intermediates partitioned between FabV and FabI in P. aeruginosa, and does either isozyme favour particular chain lengths or the unsaturated branch?
Experiment: Measure kcat/Km of purified FabV and FabI on enoyl-ACPs of each chain length, and profile acyl-ACP pools in fabV and fabI mutants by mass spectrometry.
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