title: Proteomic analysis of nalidixic acid resistance in Escherichia coli: identification and functional characterization of OM proteins.
abstract: The worldwide emergence of antibiotic-resistant bacteria poses a serious threat to human health. To understand the mechanisms of the resistance is extremely important to the control of these bacteria. In the current study, proteomic methodologies were utilized to characterize OM proteome of Escherichia coli with nalidixic acid (NA) resistance. The OM proteins TolC, OmpT, OmpC and OmpW were found to be up-regulated, and FadL was down-regulated in the NA-resistant E. coli strains. The changes at the level of protein expression were validated using Western blotting. Furthermore, the possible roles these altered proteins played in regulation of NA resistance were investigated using genetically modified strains with the deletion of these genes. The results obtained from functional characterization of these genetically modified strains suggest that TolC and OmpC may play more important roles in the control of NA resistance than other OM proteins identified. To gain better understanding of the mechanisms of NA resistance, we also characterized the role of the two-component system EnvZ/OmpR which is responsible for the regulation of OmpC and OmpF expression in response to NA resistance using their genetically modified strains. Our results suggest that OmpF and the EnvZ/OmpR are also important participants of the pathways regulating the NA resistance of E. coli.
authors.affiliation: Center for Proteomics, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
authors.forename: Xiang-Min
authors.initials: XM
authors.lastname: Lin
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.forename: Xuan-Xian
authors.initials: XX
authors.lastname: Peng
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D015536:Down-Regulation / Q000187:drug effects; D024881:Drug Resistance, Bacterial; D015180:Electrophoresis, Gel, Two-Dimensional; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D050612:Fatty Acid Transport Proteins / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D009268:Nalidixic Acid / Q000494:pharmacology*; D018272:Porins / Q000235:genetics / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D050612:Fatty Acid Transport Proteins; D026901:Membrane Transport Proteins; D009097:Multienzyme Complexes; C113724:OmpC protein; C109237:OmpF protein; D018272:Porins; D015534:Trans-Activators; C065691:fadL protein, E coli; C112177:osmolarity response regulator proteins; C073126:tolC protein, E coli; D009268:Nalidixic Acid; C057843:envZ protein, E coli