Heme A Synthase Deficiency Affects the Ability of to Adapt to a Nutrient-Limited Environment.

The branched aerobic respiratory chain in comprises three terminal oxidases: cytochromes , , and . Cytochrome requires heme A for activity, which is produced from heme O by heme A synthase (CtaA). In this study, we deleted the gene in AH187 strain, this deletion resulted in loss of cytochrome activity. Proteomics data indicated that grown in glucose-containing medium compensates for the loss of cytochrome activity by remodeling its respiratory metabolism. This remodeling involves up-regulation of cytochrome and several proteins involved in redox stress response-to circumvent sub-optimal respiratory metabolism. deletion changed the surface-composition of affecting its motility, autoaggregation phenotype, and the kinetics of biofilm formation. Strikingly, proteome remodeling made the mutant more resistant to cold and exogenous oxidative stresses compared to its parent strain. Consequently, we hypothesized that inactivation could improve fitness in a nutrient-limited environment.