A novel colicin type, designated colicin Fy, was found to be encoded and produced by the strain Yersinia frederiksenii Y27601. Colicin Fy was active against both pathogenic and nonpathogenic strains of the genus Yersinia. Plasmid YF27601 (5,574 bp) of Y. frederiksenii Y27601 was completely sequenced. The colicin Fy activity gene (cfyA) and the colicin Fy immunity gene (cfyI) were identified. The deduced amino acid sequence of colicin Fy was very similar in its C-terminal pore-forming domain to colicin Ib (69% identity in the last 178 amino acid residues), indicating pore forming as its lethal mode of action. Transposon mutagenesis of the colicin Fy-susceptible strain Yersinia kristensenii Y276 revealed the yiuR gene (ykris001_4440), which encodes the YiuR outer membrane protein with unknown function, as the colicin Fy receptor molecule. Introduction of the yiuR gene into the colicin Fy-resistant strain Y. kristensenii Y104 restored its susceptibility to colicin Fy. In contrast, the colicin Fy-resistant strain Escherichia coli TOP10F' acquired susceptibility to colicin Fy only when both the yiuR and tonB genes from Y. kristensenii Y276 were introduced. Similarities between colicins Fy and Ib, similarities between the Cir and YiuR receptors, and the detected partial cross-immunity of colicin Fy and colicin Ib producers suggest a common evolutionary origin of the colicin Fy-YiuR and colicin Ib-Cir systems.

• MeSH
• Chromosomes, Bacterial genetics   MeSH
• Bacterial Proteins genetics   metabolism   MeSH
• Cell Membrane physiology   MeSH
• Escherichia coli genetics   metabolism   MeSH
• Phylogeny MeSH
• Genotype MeSH
• Cloning, Molecular MeSH
• Colicins metabolism   pharmacology   MeSH
• Membrane Proteins genetics   metabolism   MeSH
• Molecular Sequence Data MeSH
• Plasmids genetics   MeSH
• Gene Expression Regulation, Bacterial physiology   MeSH
• Amino Acid Sequence MeSH
• Yersinia drug effects   genetics   metabolism   pathogenicity   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Bacterial Proteins MeSH
• Colicins MeSH
• Membrane Proteins MeSH
• tonB protein, Bacteria MeSH Browser

Colicins are toxic exoproteins produced by bacteria of colicinogenic strains of Escherichia coli and some related species of Enterobacteriaceae, during the growth of their cultures. They inhibit sensitive bacteria of the same family. About 35% E. coli strains appearing in human intestinal tract are colicinogenic. Synthesis of colicins is coded by genes located on Col plasmids. Until now more than 34 types of colicins have been described, 21 of them in greater detail, viz. colicins A, B, D, E1-E9, Ia, Ib, JS, K, M, N, U, 5, 10. In general, their interaction with sensitive bacteria includes three steps: (1) binding of the colicin molecule to a specific receptor in the bacterial outer membrane; (2) its translocation through the cell envelope; and (3) its lethal interaction with the specific molecular target in the cell. The classification of colicins is based on differences in the molecular events of these three steps.

• MeSH
• Escherichia coli chemistry   metabolism   MeSH
• Escherichia coli Infections microbiology   MeSH
• Colicins classification   metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Names of Substances
• Colicins MeSH