Coordination of bacterial cell wall and outer membrane biosynthesis
Katherine R Hummels1, Samuel P Berry2, Zhaoqi Li1
1Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
Nature
|March 1, 2023
Summary
Researchers discovered a direct interaction between key enzymes MurA and LpxC in Gram-negative bacteria. This interaction coordinates the synthesis of the peptidoglycan (PG) cell wall and lipopolysaccharide (LPS) outer membrane, crucial for antibiotic resistance.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Gram-negative bacteria possess a complex cell envelope comprising a cytoplasmic membrane, peptidoglycan (PG) cell wall, and an outer membrane (OM) with lipopolysaccharide (LPS).
- This envelope acts as a barrier to antibiotics, contributing to intrinsic antibiotic resistance.
- While PG and OM biogenesis pathways are known, their coordination remains poorly understood.
Purpose of the Study:
- To investigate the molecular mechanisms coordinating the biogenesis of the Gram-negative bacterial envelope.
- To identify potential regulatory interactions between enzymes involved in PG and LPS synthesis.
Main Methods:
- Investigated the interaction between PG synthesis enzyme MurA and LPS synthesis enzyme LpxC in Pseudomonas aeruginosa.
- Utilized cellular and purified systems to assess the functional impact of the MurA-LpxC interaction.
Main Results:
- Discovered a direct and specific interaction between MurA and LpxC.
- Demonstrated that MurA stimulates LpxC activity both in vivo and in vitro.
- This interaction links the committed enzymes of PG and LPS synthesis pathways.
Conclusions:
- The assembly of the Gram-negative envelope is coordinated by a regulatory interaction between MurA and LpxC.
- This finding provides a model for how PG and OM biogenesis are linked in proteobacteria.
- Understanding this coordination may lead to novel therapeutic strategies against drug-resistant Gram-negative infections.
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