A cryptic long-chain 3-ketoacyl-ACP synthase in the Pseudomonas putida F1 unsaturated fatty acid synthesis pathway
| Autor: | Yu-Ling Liao, Lujie Liang, John E. Cronan, Bo Chen, Haihong Wang, Jin-Cheng Ma, Huijuan Dong, Yu-Lu Song, Qunyi Chen |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
0301 basic medicine
ACP acyl carrier protein Operon Auxotrophy SFA saturated fatty acid Repressor Biochemistry 03 medical and health sciences 3-Oxoacyl-(Acyl-Carrier-Protein) Synthase 3-ketoacyl-ACP synthase UFA unsaturated fatty acid Molecular Biology Unsaturated fatty acid fatty acid oxidation 030102 biochemistry & molecular biology biology Chemistry Pseudomonas putida Genetic Complementation Test repressor protein Cell Biology biology.organism_classification Complementation Acyl carrier protein 030104 developmental biology fatty acid metabolism regulator Saturated fatty acid biology.protein Fatty Acids Unsaturated fatty acid synthase (FAS) Research Article |
| Zdroj: | The Journal of Biological Chemistry |
| ISSN: | 1083-351X |
| Popis: | The Pseudomonas putida F1 genome contains five genes annotated as encoding 3-ketoacyl-acyl carrier protein (ACP) synthases. Four are annotated as encoding FabF (3-ketoacyl-ACP synthase II) proteins, and the fifth is annotated as encoding a FabB (3-ketoacyl-ACP synthase I) protein. Expression of one of the FabF proteins, FabF2, is cryptic in the native host and becomes physiologically important only when the repressor controlling fabF2 transcription is inactivated. When derepressed, FabF2 can functionally replace FabB, and when expressed from a foreign promoter, had weak FabF activity. Complementation of Escherichia coli fabB and fabF mutant strains with high expression showed that P. putida fabF1 restored E. coli fabF function, whereas fabB restored E. coli fabB function and fabF2 restored the functions of both E. coli fabF and fabB. The P. putida ΔfabF1 deletion strain was almost entirely defective in synthesis of cis-vaccenic acid, whereas the ΔfabB strain is an unsaturated fatty acid (UFA) auxotroph that accumulated high levels of spontaneous suppressors in the absence of UFA supplementation. This was due to increased expression of fabF2 that bypasses loss of fabB because of the inactivation of the regulator, Pput_2425, encoded in the same operon as fabF2. Spontaneous suppressor accumulation was decreased by high levels of UFA supplementation, whereas competition by the P. putida β-oxidation pathway gave increased accumulation. The ΔfabB ΔfabF2 strain is a stable UFA auxotroph indicating that suppressor accumulation requires FabF2 function. However, at low concentrations of UFA supplementation, the ΔfabF2 ΔPput_2425 double-mutant strain still accumulated suppressors at low UFA concentrations. |
| Databáze: | OpenAIRE |
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