The voltage-dependent gating of the colicin channel involves a substantial structural rearrangement that results in the transfer of about 35% of the 200 residues in its pore-forming domain across the membrane. This transfer appears to represent an unusual type of protein translocation that does not depend on a large, multimeric, protein pore. To investigate the ability of this system to transport arbitrary proteins, we made use of a pair of strongly interacting proteins, either of which could serve as a translocated cargo or as a probe to detect the other. Here we show that both an 86-residue and a 134-residue hydrophilic protein inserted into the translocated segment of colicin A are themselves translocated and are functional on the trans side of the bilayer. The disparate features of these proteins suggest that the colicin channel has a general protein translocation mechanism.
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http://dx.doi.org/10.1073/pnas.022480199 | DOI Listing |
Minerva Med
February 2024
Department of Stomatology, Xi'an International Medical Center Hospital Affiliated to Northwest University, Xi'an, Shaanxi, China -
Environ Microbiol
May 2023
Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, Life Science College, Fujian Agriculture and Forestry University, Fuzhou, China.
The colicin I receptor (CirA) is a well-studied outer membrane protein that has been reported to play important roles in antibiotic resistance, virulence, and iron homeostasis, although its exact physiological roles require further investigation. In this study, differentially expressed proteins between the ΔahcirA and wild-type (WT) strains of Aeromonas hydrophila were compared using quantitative proteomics. Bioinformatics analysis revealed that the expression of peptide, histidine, and arginine ATP-binding cassette (ABC) transporter system-related proteins was significantly higher in the ΔahcirA strain.
View Article and Find Full Text PDFElife
February 2022
Center for Computational Biology, The University of Kansas, Lawrence, United States.
The double membrane architecture of Gram-negative bacteria forms a barrier that is impermeable to most extracellular threats. Bacteriocin proteins evolved to exploit the accessible, surface-exposed proteins embedded in the outer membrane to deliver cytotoxic cargo. Colicin E1 is a bacteriocin produced by, and lethal to, that hijacks the outer membrane proteins (OMPs) TolC and BtuB to enter the cell.
View Article and Find Full Text PDFComput Struct Biotechnol J
September 2021
Department of Biochemistry and Microbiology, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok 10330, Thailand.
Colicin N (ColN) is a bacteriocin secreted by () to kill other Gram-negative bacteria by forcefully generating ion channels in the inner membrane. In addition to its bactericidal activity, ColN have been reported to selectively induce apoptosis in human lung cancer cells via the suppression of integrin modulated survival pathway. However, ColN showed mild toxicity against human lung cancer cells which could be improved for further applications.
View Article and Find Full Text PDFMol Biol Evol
September 2021
Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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