1. Interaction of the Colicin K Bactericidal Toxin with Components of Its Import Machinery in the Periplasm of Escherichia coli
- Author
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Aurélie Barnéoud-Arnoulet, Marthe Gavioli, Roland Lloubès, Eric Cascales, Laboratoire d'ingénierie des systèmes macromoléculaires (LISM), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Aix Marseille Université (AMU), and Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Signal peptide ,[SDV]Life Sciences [q-bio] ,Colicins ,Biology ,medicine.disease_cause ,Microbiology ,Microbial Cell Biology ,03 medical and health sciences ,Protein Interaction Mapping ,Escherichia coli ,medicine ,Immunoprecipitation ,Outer membrane efflux proteins ,Molecular Biology ,030304 developmental biology ,0303 health sciences ,030306 microbiology ,Escherichia coli Proteins ,Membrane Proteins ,Periplasmic space ,3. Good health ,Cell biology ,Transport protein ,Protein Transport ,Biochemistry ,Membrane protein ,Colicin ,bacteria ,Periplasmic Proteins ,Bacterial outer membrane ,Protein Binding - Abstract
Colicins are bacterial antibiotic toxins produced by Escherichia coli cells and are active against E. coli and closely related strains. To penetrate the target cell, colicins bind to an outer membrane receptor at the cell surface and then translocate their N-terminal domain through the outer membrane and the periplasm. Once fully translocated, the N-terminal domain triggers entry of the catalytic C-terminal domain by an unknown process. Colicin K uses the Tsx nucleoside-specific receptor for binding at the cell surface, the OmpA protein for translocation through the outer membrane, and the TolABQR proteins for the transit through the periplasm. Here, we initiated studies to understand how the colicin K N-terminal domain (KT) interacts with the components of its transit machine in the periplasm. We first produced KT fused to a signal sequence for periplasm targeting. Upon production of KT in wild-type strains, cells became partly resistant to Tol-dependent colicins and sensitive to detergent, released periplasmic proteins, and outer membrane vesicles, suggesting that KT interacts with and titrates components of its import machine. Using a combination of in vivo coimmunoprecipitations and in vitro pulldown experiments, we demonstrated that KT interacts with the TolA, TolB, and TolR proteins. For the first time, we also identified an interaction between the TolQ protein and a colicin translocation domain.
- Published
- 2010