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The phosphatidic acid pathway enzyme PlsX plays both catalytic and channeling roles in bacterial phospholipid synthesis.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2020 Feb 14; Vol. 295 (7), pp. 2148-2159. Date of Electronic Publication: 2020 Jan 09. - Publication Year :
- 2020
-
Abstract
- PlsX is the first enzyme in the pathway that produces phosphatidic acid in Gram-positive bacteria. It makes acylphosphate from acyl-acyl carrier protein (acyl-ACP) and is also involved in coordinating phospholipid and fatty acid biosyntheses. PlsX is a peripheral membrane enzyme in Bacillus subtilis, but how it associates with the membrane remains largely unknown. In the present study, using fluorescence microscopy, liposome sedimentation, differential scanning calorimetry, and acyltransferase assays, we determined that PlsX binds directly to lipid bilayers and identified its membrane anchoring moiety, consisting of a hydrophobic loop located at the tip of two amphipathic dimerization helices. To establish the role of the membrane association of PlsX in acylphosphate synthesis and in the flux through the phosphatidic acid pathway, we then created mutations and gene fusions that prevent PlsX's interaction with the membrane. Interestingly, phospholipid synthesis was severely hampered in cells in which PlsX was detached from the membrane, and results from metabolic labeling indicated that these cells accumulated free fatty acids. Because the same mutations did not affect PlsX transacylase activity, we conclude that membrane association is required for the proper delivery of PlsX's product to PlsY, the next enzyme in the phosphatidic acid pathway. We conclude that PlsX plays a dual role in phospholipid synthesis, acting both as a catalyst and as a chaperone protein that mediates substrate channeling into the pathway.<br /> (© 2020 Sastre et al.)
- Subjects :
- Bacillus subtilis genetics
Bacillus subtilis metabolism
Catalysis
Escherichia coli genetics
Escherichia coli metabolism
Fatty Acids metabolism
Lipogenesis genetics
Phosphatidic Acids genetics
Phospholipids genetics
Bacterial Proteins genetics
Metabolic Networks and Pathways genetics
Phosphatidic Acids metabolism
Phospholipids biosynthesis
Subjects
Details
- Language :
- English
- ISSN :
- 1083-351X
- Volume :
- 295
- Issue :
- 7
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 31919098
- Full Text :
- https://doi.org/10.1074/jbc.RA119.011147