The bacteriocin lactococcin A specifically increases permeability of lactococcal cytoplasmic membranes in a voltage-independent, protein-mediated manner
| Autor: | Jan Kok, Ingolf F. Nes, Wn Konings, T Abee, H Holo, M J van Belkum, Gerhardus Venema |
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| Jazyk: | angličtina |
| Rok vydání: | 1991 |
| Předmět: |
Cell Membrane Permeability
Biology IMMUNITY PEP-5 Microbiology VESICLES Membrane Potentials Cell membrane AMINO-ACID TRANSPORT Bacteriocin BILAYER-MEMBRANES Bacteriocins medicine Amino Acids Electrochemical gradient Molecular Biology Chemiosmosis DEPENDENT CHANNELS Vesicle Lactococcus lactis Cell Membrane Membrane transport ARTIFICIAL MEMBRANES biology.organism_classification STREPTOCOCCUS-CREMORIS Kinetics Microscopy Electron medicine.anatomical_structure Biochemistry Membrane protein Liposomes bacteria COLICIN-A PLASMID Research Article |
| Zdroj: | Journal of Bacteriology, 173(24), 7934-7941. AMER SOC MICROBIOLOGY |
| ISSN: | 0021-9193 |
| Popis: | Lactococcin A is a bacteriocin produced by Lactococcus lactis. Its structural gene has recently been cloned and sequenced (M. J. van Belkum, B. J. Hayema, R. E. Jeeninga, J. Kok, and G. Venema, Appl. Environ. Microbiol. 57:492-498, 1991). Purified lactococcin A increased the permeability of the cytoplasmic membrane of L. lactis and dissipated the membrane potential. A significantly higher concentration of lactococcin A was needed to dissipate the membrane potential in an immune strain of L. lactis. Lactococcin A at low concentrations (0.029 microgram/mg of protein) inhibited secondary and phosphate-bond driven transport of amino acids in sensitive cells and caused efflux of preaccumulated amino acids. Accumulation of amino acids by immune cells was not affected by this concentration of lactococcin A. Lactococcin A also inhibited proton motive force-driven leucine uptake and leucine counterflow in membrane vesicles of the sensitive strain but not in membrane vesicles of the immune strain. These observations indicate that lactococcin A makes the membrane permeable for leucine in the presence or absence of a proton motive force and that the immunity factor(s) is membrane linked. Membrane vesicles of Clostridium acetobutylicum, Bacillus subtilis, and Escherichia coli were not affected by lactococcin A, nor were liposomes derived from phospholipids of L. lactis. These results indicate that lactococcin A acts on the cytoplasmic membrane and is very specific towards lactococci. The combined results obtained with cells, vesicles, and liposomes suggest that the specificity of lactococcin A may be mediated by a receptor protein associated with the cytoplasmic membrane. |
| Databáze: | OpenAIRE |
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