Role of Sinorhizobium meliloti and Escherichia coli Long-Chain Acyl-CoA Synthetase FadD in Long-Term Survival

Abstract

FadD is an acyl-coenzyme A (CoA) synthetase specific for long-chain fatty acids (LCFA). Strains mutated in fadD cannot produce acyl-CoA and thus cannot grow on exogenous LCFA as the sole carbon source. Mutants in the fadD (smc02162) of Sinorhizobium meliloti are unable to grow on oleate as the sole carbon source and present an increased surface motility and accumulation of free fatty acids at the entry of the stationary phase of growth. In this study, we found that constitutive expression of the closest FadD homologues of S. meliloti, encoded by sma0150 and smb20650, could not revert any of the mutant phenotypes. In contrast, the expression of Escherichia coli fadD could restore the same functions as S. meliloti fadD. Previously, we demonstrated that FadD is required for the degradation of endogenous fatty acids released from membrane lipids. Here, we show that absence of a functional fadD provokes a significant loss of viability in cultures of E. coli and of S. meliloti in the stationary phase, demonstrating a crucial role of fatty acid degradation in survival capacity.

Gut Microbial SNPs Induced by High-Fiber Diet Dominate Nutrition Metabolism and Environmental Adaption of Faecalibacterium prausnitzii in Obese Children

“…The gene pyk encodes pyruvate kinase (Gubler et al, 1994), mainly taking part in glycolysis/gluconeogenesis (ko00010), purine metabolism (ko00230), and pyruvate metabolism (ko00620). The gene fadD encodes long-chain acyl-CoA synthetase that can use long-chain fatty acids as carbon source and energy (Pech-Canul et al, 2020), and is mainly involved in fatty acid biosynthesis and degradation (ko00061 and ko00071), ferroptosis (ko04216), lipid biosynthesis proteins (ko01004), quorum sensing (ko02024), thermogenesis (ko04714), etc.…”

Specialized acyl carrier protein used by serine palmitoyltransferase to synthesize sphingolipids in Rhodobacteria

“…Recloning of the CC_1163/CC_1162 ( acpR/spt )-encoding Nde I/ Bam HI fragment from pRJ03 ( Olea-Ozuna et al, 2021 ) into a Nde I/ Bgl II-restricted pCDFDuet-1 (MCS-2) vector yielded plasmid pJPG16. Recloning of the smc02162 ( fadD )-encoding Nde I/ Hind III fragment from pECH6 ( Pech-Canul et al, 2020 ) into a Nde I/ Hind III-restricted pET28a vector yielded plasmid pECH3.…”

“…Ritsema et al, 1998Epple et al, 1998López-Lara and Geiger, 2000Ramos-Vega et al, 2009Pech-Canul et al, 2020Olea-Ozuna et al, 2021Olea-Ozuna et al, 2021Olea-Ozuna et al, 2021 …”

Degradation of Exogenous Fatty Acids in Escherichia coli

“…PLs and LPS are constantly synthesized, modified, and destroyed to maintain membrane homeostasis and to respond to environmental stressors. Free FAs can be released during these processes, serving as signaling molecules for the regulation of the LPS levels or providing an extra carbon source when other sources are depleted [ 2 , 6 , 7 ]. Nonetheless, the main source of free FAs remains the surrounding environment.…”

“…However, it is possible that the Fad machinery might also be involved in other roles than exogenous FA consumption. Indeed, it has been proposed that in the stationary phase, free FAs are released due to the recycling of the envelope and its phospholipids, and that these FAs are processed by the Fad enzymes [ 6 , 7 ]. This certainly must be put in relation with the upregulation of fad genes in the stationary phase, and the involvement of the different global regulators ppGpp, RpoS, and CRP should be assessed within this context.…”