The lethal cargo of Myxococcus xanthus outer membrane vesicles

Area of Science:

• Microbiology
• Bacterial Predation
• Extracellular Vesicles

Background:

• Myxococcus xanthus is a predatory bacterium using a 'wolf pack' strategy.
• Outer membrane vesicles (OMVs) are abundant in M. xanthus and form extracellular structures.
• OMVs are hypothesized to deliver enzymes and antibiotics for prey capture.

Purpose of the Study:

• To characterize and compare the protein and small molecule cargo of M. xanthus OMVs and membrane fractions.
• To identify OMV-specific or enriched proteins and small molecules.
• To investigate the role of identified hydrolytic enzymes in M. xanthus extracellular activity.

Main Methods:

• Proteomic analysis of OMVs and membrane fractions.
• Small molecule profiling of OMVs.
• Genetic disruption of candidate genes (e.g., mepA) and assessment of extracellular protease activity.

Main Results:

• Identification of OMV-specific/enriched proteins, including putative hydrolytic enzymes.
• Detection of 16 small molecules in OMVs, many with antibiotic properties.
• Disruption of MXAN_3564 (mepA) significantly reduced extracellular protease activity, implicating MepA in this function.

Conclusions:

• M. xanthus OMVs carry a cargo of hydrolytic enzymes and antibiotics potentially mediating predatory behavior.
• MepA is identified as a key component of the M. xanthus extracellular protease system.
• OMVs play a crucial role in the ecological interactions and predatory strategies of M. xanthus.