1. Wprowadzenie. 2. Klasyfikacja bakteriocyn bakterii Gram-ujemnych. 3. Produkcja kolicyn przez bakterie kolicynogenne. 3.1. Synteza kolicyn. 3.2. Eksport kolicyn z komórek producenta. 4. Mechanizmy działania kolicyn. 4.1. Translokacja. 4.2. Efekt letalny kolicyn. 5. Charakterystyka i podział mikrocyn. 5.1. Struktura i genetyka wybranych mikrocyn. 5.1.1. MccE492. 5.1.2. MccJ25. 5.1.3. MccC7-C51. 5.2. Mechanizmy działania mikrocyn. 5.2.1. MccE492. 5.2.2. MccJ25. 5.2.3. MccC7-C51. 6. Potencjalne zastosowanie kolicyn i mikrocyn. 7. Podsumowanie
Abstract: Bacteriocins are a diverse group of ribosomally synthesized peptides or proteins secreted by bacteria, which help them to compete in their local environments for the limited nutritional resources. Bacteriocins kill or inhibit the growth of other bacteria. Generally, these molecules have a narrow spectrum of antibacterial activity, but some of them demonstrate a broad spectrum of action. Bacteriocins from Gram-negative bacteria are divided into two main groups: high molecular mass proteins (30–80 kDa) known as colicins, and low molecular mass peptides (between 1–10 kDa) termed microcins. Colicins are produced by Escherichia coli strains harbouring a colicinogenic plasmid. Such colicinogenic strains are widespread in nature and are especially abundant in the gut of animals. The biosynthesis of colicins is mediated by the SOS regulon, which becomes activated in the response to DNA damage. The colicin synthesis is lethal for the producing cells as a consequence of the concomitant biosynthesis of the colicin lysis protein. Microcins are usually highly stable molecules, which are resistant to proteases, extreme pH values and temperatures. They are produced by enteric bacteria under stress conditions, particularly nutrient depletion. Microcins are encoded by gene clusters carried by plasmids or in certain cases by the chromosome. In this review, we have summarized the most important information about structure and properties of bacteriocins from Gram-negative bacteria, their diverse mechanisms of action and potential application as food preservatives and in livestock industry.
1. Introduction. 2. Classification of bacteriocins from Gram-negative bacteria. 3. Production of colicins by colicinogenic bacteria. 3.1. Colicin synthesis. 3.2. Export of colicins from bacteriocin-producing cells. 4. Modes of colicin action. 4.1. Translocation. 4.2. Lethal effect of colicins. 5. Characteristics and classification of microcins. 5.1. Structure and genetics of selected microcins. 5.1.1. MccE492. 5.1.2. MccJ25. 5.1.3. MccC7-C51. 5.2. Mechanisms of action of microcins. 5.2.1. MccE492. 5.2.2. MccJ25. 5.2.3. MccC7-C51. 6. Potential applications of colicins and microcins. 7. Summary