Annotation inferences using phylogenetic trees
Gene Ontology annotation based on UniPathway vocabulary mapping
Combined Automated Annotation using Multiple IEA Methods
Coupling of fatty acid and phospholipid synthesis in Bacillus subtilis.
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Conditional inactivation of PlsY in B. subtilis blocks phospholipid synthesis while fatty acid synthesis continues, and B. subtilis membranes acylate glycerol 3-phosphate using acyl-phosphate, not acyl-ACP or acyl-CoA.
"Analysis of glycerol 3-P acylation in B."
Involvement of the YneS/YgiH and PlsX proteins in phospholipid biosynthesis in both Bacillus subtilis and Escherichia coli.
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yneS (plsY) is essential in B. subtilis; at the restrictive temperature a yneS temperature-sensitive strain makes no phospholipid, and the phenotype is suppressed by raising intracellular glycerol 3-phosphate.
"no phospholipids were detectable in yneS-ts cells following a shift to the restrictive temperature"
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Suppression by glpD inactivation or by glycerol/glycerol 3-phosphate feeding shows that glycerol 3-phosphate availability modulates the residual activity of PlsY in vivo.
"supplementation of the growth medium (LB) with 0.1% (w/v) G3P, or glycerol, complemented the yneS-ts phenotype"
Involvement of PlsX and the acyl-phosphate dependent sn-glycerol-3-phosphate acyltransferase PlsY in the initial stage of glycerolipid synthesis in Bacillus subtilis.
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Membranes of a plsY deletion strain lose acyl-phosphate-dependent glycerol 3-phosphate acylation, establishing PlsY as the acyl-phosphate-dependent GPAT of B. subtilis.
"The results indicate unequivocally that PlsY is an acyl-phosphate dependent GPAT."
Bacterial lipid synthesizing enzymes PlsY and PlsC utilize both stereo-forms of glycerol-phosphate.
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Purified B. subtilis and E. coli PlsY acylate both sn-glycerol 3-phosphate and sn-glycerol 1-phosphate in detergent, with only minor differences in product levels, whereas PlsB is strictly specific for glycerol 3-phosphate.
"Remarkably, the addition of glycerol 3-phosphate, as well as glycerol 1-phosphate, resulted in the substantial production of LPA, with only minor differences in quantities over time."
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When PlsY is reconstituted into liposomes the glycerol 3-phosphate product predominates significantly, so the near-equal use of the two enantiomers is a property of the detergent assay rather than of the membrane-embedded enzyme.
"However, the levels of (R)-LPA (containing a G3P lipid backbone) were significantly higher compared to the levels of (S)-LPA, a difference that was not observed for the enzyme in detergent (Fig."
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The authors infer that in vivo heterochirality of B. subtilis phosphatidylglycerol follows from PlsY being the sole GPAT; this is a consistency argument, not a measurement in cells, and the authors state that kinetic analysis is still required.
"As in this microorganism, PlsY is its sole GPAT, the observed in vivo heterochirality is in line with our in vitro observations."
Chiral analysis of glycerol phosphates - can bacteria biosynthesize heterochiral phospholipid membranes?
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Both glycerol-phosphate enantiomers were detected in B. subtilis and three other Gram-positive bacteria, with a 4:1 ratio of glycerol 3-phosphate to glycerol 1-phosphate, and both enantiomers were found in the glycerol backbone of some phosphatidylglycerol species.
"By using chiral chromatography, the presence of both enantiomers in the glycerol backbone of some molecular species of PG was revealed."
Essential Bacillus subtilis genes.
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Systematic inactivation identified a small set of indispensable B. subtilis genes; plsC (yhdO) and plsX are among them, and this work is the source of the essentiality claim used for the PlsX/PlsY pathway.
"Among approximately 4,100 genes of the organism, only 192 were shown to be indispensable by this or previous work."