Metabolic Reprogramming ofVibrio choleraeImpaired in Respiratory NADH Oxidation Is Accompanied by Increased Copper Sensitivity
ABSTRACTThe electrogenic, sodium ion-translocating NADH:quinone oxidoreductase (NQR) fromVibrio choleraeis frequent in pathogenic bacteria and a potential target for antibiotics. NQR couples the oxidation of NADH to the formation of a sodium motive force (SMF) and therefore drives important processes, such as flagellar rotation, substrate uptake, and energy-dissipating cation-proton antiport. We performed a quantitative proteome analysis ofV. choleraeO395N1 compared to its variant lacking the NQR using minimal medium with glucose as the carbon source. We found 84 proteins (regulation factor of ≥2) to be changed in abundance. The loss of NQR resulted in a decrease in the abundance of enzymes of the oxidative branch of the tricarboxylic acid (TCA) cycle and an increase in abundance of virulence factors AcfC and TcpA. Most unexpected, the copper resistance proteins CopA, CopG, and CueR were decreased in thenqrdeletion strain. As a consequence, the mutant exhibited diminished resistance to copper compared to the reference strain, as confirmed in growth studies using either glucose or mixed amino acids as carbon sources. We propose that the observed adaptations of thenqrdeletion strain represent a coordinated response which counteracts a drop in transmembrane voltage that challengesV. choleraein its different habitats.IMPORTANCEThe importance of the central metabolism for bacterial virulence has raised interest in studying catabolic enzymes not present in the host, such as NQR, as putative targets for antibiotics.Vibrio choleraelacking the NQR, which is studied here, is a model to estimate the impact of specific NQR inhibitors on the phenotype of a pathogen. Our comparative proteomic study provides a framework to evaluate the chances of success of compounds directed against NQR with respect to their bacteriostatic or bactericidal action.