The Tol-OprL System of Pseudomonas

摘要: The cell envelope of gram-negative bacteria constitutes a barrier to the entry many compounds, including deleterious agents, into cytoplasm. Our early knowledge about structure and function this component was based mainly on studies with Escherichia coli 84, 96, 97. Early attempts better understand microorganism led analysis genotypic phenotypic properties bacterial strains mutated in genes encoding membrane components. An easy way obtain such mutants isolate those E. insensitive lethal action colicins. Colicins are toxins, encoded by plasmids, that produced active against closely related bacteria108, 109. Independent their mode (nuclease or pore-forming activity), these bacteriocins, which generally released large amounts extracellular medium, must cross order reach final targets. mechanisms some colicins enter cells have been extensively studied17, 54, 64 –67, 118. First, bind cells, recognize specific receptor outer membrane. Bacteria carrying mutations receptors do not respective colicin are, therefore, its action. These termed colicin-resistant. After binding surface receptor, is translocated through envelope. Mutants isolated, terned colicin-tolerant, allow absorb but toxic effect.