title: Colicins U and Y inhibit growth of Escherichia coli strains via recognition of conserved OmpA extracellular loop 1.
abstract: Interactions of colicins U and Y with the OmpA (Outer membrane protein A) receptor molecule were studied using site-directed mutagenesis and colicin binding assay. A systematic mutagenesis of the colicin-susceptible OmpA sequence from Escherichia coli (OmpAEC) to the colicin-resistant OmpA sequence from Serratia marcescens (OmpASM) was performed in regions corresponding to extracellular OmpA loops 1-4. Susceptibility to colicins U and Y was significantly affected by the OmpA mutation in loop 1. As with functional analysis, a decrease in binding capacity of His-tagged colicin U was found for recombinant OmpA with a mutated segment in loop 1 compared to control OmpAEC. To verify the importance of the identified amino acid residues in OmpA loop 1, we introduced loop 1 from OmpAECinto OmpASM, which resulted in the substantial increase of susceptibility to colicins U and Y. In addition, colicins U and Y were tested against a panel of 118 bacteriocin non-producing strains of four Escherichia species, including E. coli (39 strains), E. fergusonii (10 strains), E. hermannii (42 strains), and E. vulneris (27 strains). A majority (82%) of E. coli strains was susceptible to colicins U and Y. Interestingly, colicins U and Y also inhibited all of the 30 tested multidrug-resistant E. coli O25b-ST131 isolates. These findings, together with the fact that OmpA loop 1 is important for bacterial virulence and is evolutionary conserved, offer the potential of using colicins U and Y as specific anti-OmpA loop 1 directed antibacterial proteins.
authors: Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 5, Building A6, 625 00 Brno, Czech Republic.
authors: Juraj
authors: J
authors: Bosák
authors: Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 5, Building A6, 625 00 Brno, Czech Republic.
authors: Lenka
authors: L
authors: Micenková
authors: Department of Environment Protection Engineering, Faculty of Technology, Tomas Bata University in Zlín, T. G. Masaryk square 275, Zlín, Czech Republic.
authors: Magda
authors: M
authors: Doležalová
authors: Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 5, Building A6, 625 00 Brno, Czech Republic. Electronic address: dsmajs@med.muni.cz.
authors: David
authors: D
authors: Šmajs
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D003087:Colicins / Q000378:metabolism*; D004252:DNA Mutational Analysis; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development*; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D011485:Protein Binding; D012706:Serratia marcescens / Q000235:genetics
chemical_list: D001425:Bacterial Outer Membrane Proteins; D003087:Colicins; C078167:OMPA outer membrane proteins
keywords: Colicin U; Colicin Y; Colicin-receptor interaction; Escherichia coli; OmpA