Colicin U from Shigella boydii Forms Voltage-Dependent Pores

DOLEJSOVA, Tereza, Albert SOKOL, Juraj BOSÁK, David ŠMAJS, Ivo KONOPASEK, Gabriela MIKUSOVA and Radovan FISER. Colicin U from Shigella boydii Forms Voltage-Dependent Pores. Journal of Bacteriology. Washington: American Society for Microbiology, 2019, vol. 201, No 24, p. 1-16. ISSN 0021-9193. Available from: https://dx.doi.org/10.1128/JB.00493-19.

Basic information

• Original name: Colicin U from Shigella boydii Forms Voltage-Dependent Pores
• Authors: DOLEJSOVA, Tereza (203 Czech Republic), Albert SOKOL (203 Czech Republic), Juraj BOSÁK (703 Slovakia, belonging to the institution), David ŠMAJS (203 Czech Republic, belonging to the institution), Ivo KONOPASEK (203 Czech Republic), Gabriela MIKUSOVA (203 Czech Republic) and Radovan FISER (203 Czech Republic, guarantor).
• Edition: Journal of Bacteriology, Washington, American Society for Microbiology, 2019, 0021-9193.

Other information

• Original language: English
• Type of outcome: Article in a journal
• Field of Study: 10606 Microbiology
• Country of publisher: United States of America
• Confidentiality degree: is not subject to a state or trade secret
• WWW: URL
• Impact factor: Impact factor: 3.006
• RIV identification code: RIV/00216224:14110/19:00108046
• Organization unit: Faculty of Medicine
• Doi: http://dx.doi.org/10.1128/JB.00493-19
• UT WoS: 000497968700004
• Keywords in English: colicin U; Shigella boydii; black lipid membrane; membrane pores; ion-selectivity
• Tags: 14110513, rivok

Abstract

Colicin U is a protein produced by the bacterium Shigeo boydii (serovars 1 and 8). It exerts antibacterial activity against strains of the enterobacterial genera Shigella and Escherichia. Here, we report that colicin U forms voltage-dependent pores in planar lipid membranes; its single-pore conductance was found to be about 22 p5 in 1 M KCl at pH 6 under 80 mV in asolectin bilayers. In agreement with the high degree of homology between their C-terminal domains, colicin U shares some pore characteristics with the related colicins A and B. Colicin U pores are strongly pH dependent, and as we deduced from the activity of colicin U in planar membranes at different protein concentrations, they have a monomeric pore structure. However, in contrast to related colicins, we observed a very low cationic selectivity of colicin U pores (1.5/1 of K+/Cl- at pH 6) along with their atypical voltage gating. Finally, using nonelectrolytes, we determined the inner diameter of the pores to be in the range of 0.7 to 1 nm, which is similar to colicin la, but with a considerably different inner profile. IMPORTANCE Currently, a dramatic increase in antibiotic resistance is driving researchers to find new antimicrobial agents. The large group of toxins called bacteriocins appears to be very promising from this point of view, especially because their narrow killing spectrum allows specific targeting against selected bacterial strains. Colicins are a subgroup of bacteriocins that act on Gram-negative bacteria. To date, some colicins are commercially used for the treatment of animals (1) and tested as a component of engineered species-specific antimicrobial peptides, which are studied for the potential treatment of humans (2). Here, we present a thorough single-molecule study of colicin U which leads to a better understanding of its mode of action. It extends the range of characterized colicins available for possible future medical applications.

Links

• GA16-21649S, research and development project: Name: Molekulární charakterizace nových bakteriocinů identifikovaných v rodech Escherichia a Shigella

Investor: Czech Science Foundation