Membrane Remodeling by a Bacterial Phospholipid-Methylating Enzyme.

Area of Science:

• Microbiology
• Biochemistry
• Cell Biology

Background:

• Membrane deformation by proteins is well-studied in eukaryotes but less so in prokaryotes.
• Phospholipid N-methyltransferase PmtA from Agrobacterium tumefaciens catalyzes phosphatidylethanolamine to phosphatidylcholine conversion.

Purpose of the Study:

• To investigate the membrane-deforming activity of PmtA.
• To define the lipid and protein requirements for PmtA's membrane-remodeling function.

Main Methods:

• Transmission electron microscopy
• Liposome interaction studies
• In vivo and in vitro analyses

Main Results:

• PmtA alters liposome shape into filaments or vesicles depending on lipid composition.
• Overproduction of PmtA in Agrobacterium tumefaciens leads to cytoplasmic vesicle formation, dependent on cardiolipin.
• The N-terminal lipid-binding alpha-helix (αA) of PmtA is crucial for membrane deformation, with distinct regions for membrane recruitment and remodeling.

Conclusions:

• PmtA is identified as a novel bacterial membrane-remodeling protein.
• The study elucidates molecular requirements for PmtA-mediated membrane deformation at protein and phospholipid levels.
• Membrane biosynthesis enzymes like PmtA may contribute to bacterial membrane morphology.