Identification of a gene required for the biosynthesis of ornithine‐derived lipids

Weissenmayer, Barbara; Gao, Jun-lian; López‐Lara, Isabel M.; Geiger, Otto

doi:10.1046/j.1365-2958.2002.03043.x

Cited by 75 publications

(104 citation statements)

References 51 publications

Supporting

Mentioning

101

Contrasting

Order By: Relevance

“…The second step of ornithine lipid biosynthesis is catalyzed by the protein product of olsA (Fig. S1), which is frequently found downstream of olsB (30,31). Unexpectedly, the amino acid sequence of HTCC7211_00011010 did not cluster with OlsA sequences from characterized enzymes, despite all three having phospholipid/glycerol acyltransferase domain (IPR002123) signatures.…”

Section: Resultsmentioning

confidence: 97%

SAR11 lipid renovation in response to phosphate starvation

Carini

Mooy

Thrash

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

124

View full text Add to dashboard Cite

Phytoplankton inhabiting oligotrophic ocean gyres actively reduce their phosphorus demand by replacing polar membrane phospholipids with those lacking phosphorus. Although the synthesis of nonphosphorus lipids is well documented in some heterotrophic bacterial lineages, phosphorus-free lipid synthesis in oligotrophic marine chemoheterotrophs has not been directly demonstrated, implying they are disadvantaged in phosphate-deplete ecosystems, relative to phytoplankton. Here, we show the SAR11 clade chemoheterotroph Pelagibacter sp. str. HTCC7211 renovates membrane lipids when phosphate starved by replacing a portion of its phospholipids with monoglucosyl-and glucuronosyl-diacylglycerols and by synthesizing new ornithine lipids. Lipid profiles of cells grown with excess phosphate consisted entirely of phospholipids. Conversely, up to 40% of the total lipids were converted to nonphosphorus lipids when cells were starved for phosphate, or when growing on methylphosphonate. Cells sequentially limited by phosphate and methylphosphonate transformed >75% of their lipids to phosphorus-free analogs. During phosphate starvation, a four-gene cluster was significantly up-regulated that likely encodes the enzymes responsible for lipid renovation. These genes were found in Pelagibacterales strains isolated from a phosphate-deficient ocean gyre, but not in other strains from coastal environments, suggesting alternate lipid synthesis is a specific adaptation to phosphate scarcity. Similar gene clusters are found in the genomes of other marine α-proteobacteria, implying lipid renovation is a common strategy used by heterotrophic cells to reduce their requirement for phosphorus in oligotrophic habitats.marine phosphorus cycle | lipids | glucuronic acid | cyanobacteria | methylphosphonate M icrobes primarily assimilate phosphorus (P) in its +5 valence state (phosphate; P i ), which comprises ∼3% of total cellular mass as a structural constituent of nucleic acids and phospholipids, and is intimately involved in energy metabolism and some transport functions (via ATP hydrolysis) (1). In oligotrophic ocean gyres, P i concentrations are extremely low (0.2-1.0 nM in the Sargasso Sea; ref.2) and the availability of P i can limit bacterial and primary production (2-5). Microbes inhabiting these low P i environments have evolved numerous strategies to maintain growth and enhance their competitiveness for trace amounts of P i . These mechanisms are commonly induced by P i starvation and include one or more of the following: (i) expression of high affinity P i transporters (6); (ii) reduction of cellular P i quotas (7, 8); (iii) utilization of alternate phosphorus sources (9, 10); and (iv) polyphosphate storage and breakdown (11,12). Such strategies facilitate survival in the face of P i insufficiency.

show abstract

Section: Resultsmentioning

confidence: 97%

SAR11 lipid renovation in response to phosphate starvation

Carini

Mooy

Thrash

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

124

View full text Add to dashboard Cite

show abstract

“…Moreover, inactivation of PA4351 does not affect the fatty acid composition of the membrane (data not shown), suggesting that LptA is the main LPA acyltransferase in P. aeruginosa PAO1. The phosphate-starvation-induced PA4351 gene (Lewenza et al, 2005) encodes a protein with 50 % similarity to the OlsA acyltransferase involved in ornithine lipid synthesis in Sinorhizobium meliloti (Weissenmayer et al, 2002). It has been suggested that the present group of 'lysophosphatidic acid acyltransferases' encompasses numerous subgroups with slightly different and overlapping biochemical activities.…”

Section: Discussionmentioning

confidence: 99%

Modulation of quorum sensing in Pseudomonas aeruginosa through alteration of membrane properties

et al. 2005

View full text Add to dashboard Cite

Changes in the cellular envelope are major physiological adaptations that occur when micro-organisms encounter extreme environmental conditions. An appropriate degree of membrane fluidity is crucial for survival, and alteration of membrane lipids is an essential adaptive response. Emerging data suggest that microbial cells may recognize alterations in their membrane viscosity resulting from certain environmental changes as a trigger for adaptive cellular responses. In Pseudomonas aeruginosa, the quorum-sensing (QS) system involves a complex regulatory circuitry that coordinates the expression of genes according to a critical population density. Interestingly, it has been shown that the QS system of P. aeruginosa can also be activated by nutritional stress, independently of the cell density, and therefore may be part of a more general adaptive response to stressful environmental conditions. In order to examine the proposed link between membrane properties and stress signalling, the effects of genetically engineered alterations of the membrane phospholipid composition of P. aeruginosa PAO1 on the activation of the stringent response and the QS system were examined. The lptA gene encoding a functional homologue of PlsC, an Escherichia coli enzyme that catalyses the second step of the phospholipid biosynthesis pathway, was identified and disrupted. Inactivation of lptA altered the fatty acid profile of phospholipids and the membrane properties, resulting in decreased membrane fluidity. This resulted in a premature production of the QS signals N-butanoyl-and N-hexanoyl-homoserine lactone (C4-HSL and C6-HSL) and a repression of 2-heptyl-3-hydroxy-4-quinolone (PQS) synthesis at later growth phases. The effects on C4-and C6-HSL depended upon the expression of relA, encoding the (p)ppGpp alarmone synthase, which was increased in the lptA mutant. Together, the findings support the concept that alterations in membrane properties can act as a trigger for stress-related gene expression.

show abstract

“…Genes predicted to be involved in OL synthesis can be found in 50% of the sequenced bacterial species (1) but have not been described in eukaryotes or archaea (2,3). An OL synthesis pathway was discovered first in the ␣-proteobacterium Sinorhizobium meliloti (4,5). The N-acyltransferase OlsB transfers a 3-hydroxy fatty acyl residue from the constitutive acyl carrier protein AcpP to the ␣-amino group of ornithine forming lysoornithine lipid (4).…”

mentioning

confidence: 99%

“…The N-acyltransferase OlsB transfers a 3-hydroxy fatty acyl residue from the constitutive acyl carrier protein AcpP to the ␣-amino group of ornithine forming lysoornithine lipid (4). Then the O-acyltransferase OlsA transfers a fatty acyl residue from AcpP to the lyso-ornithine lipid, thereby yielding OL (5). Recently, the OL synthase OlsF was described in Serratia proteamaculans (1).…”

mentioning

confidence: 99%