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Inhibition of the respiratory-linked membrane potential in E. coli membrane vesicles by octapeptin
Abstract:
Octapeptin is a peptide antibiotic which affects bacterial membrane structure and selective membrane permeability for protons and potassium. The influence of octapeptin on the formation of a membrane potential generated across bacterial vesicles was monitored using the Rb+-valinomycin transport system. Octapeptin inhibited the respiratory-linked generation of membrane potentials formed in the presence of succinate or Asc/PMS. In addition, the antibiotic inhibited [3H]-leucine transport driven either by succinate or Asc/PMS. These studies support the proposal that the antimicrobial activity of octapeptin is due to inhibition of the formation of a membrane potential generated in the presence of appropriate respiratory substrates.
Insights
Octapeptin, a peptide antibiotic, disrupts bacterial membranes and proton/potassium permeability. It inhibits membrane potential generation, explaining its antimicrobial action by blocking energy production pathways.
Area of Science:
- Microbiology
- Biochemistry
- Molecular Biology
Background:
- Octapeptin is a peptide antibiotic impacting bacterial membrane structure and permeability.
- Understanding its mechanism is crucial for developing new antimicrobial strategies.
Purpose of the Study:
- To investigate the effect of octapeptin on membrane potential generation in bacterial vesicles.
- To elucidate the role of membrane potential in octapeptin's antimicrobial activity.
Main Methods:
- Monitoring membrane potential using the Rb+-valinomycin transport system.
- Assessing [3H]-leucine transport inhibition.
Main Results:
- Octapeptin inhibited respiratory-linked membrane potential generation with succinate or Asc/PMS.
- The antibiotic also inhibited [3H]-leucine transport driven by these substrates.
Conclusions:
- Octapeptin's antimicrobial activity is attributed to its inhibition of membrane potential formation.
- This disruption affects essential cellular processes like nutrient transport.