Thiol stress induces catalaseA in Streptomyces coelicolor

Streptomyces coelicolor, a gram positive bacterium, lacking glutathione was selected as a model organism for characterizing the enzymes involved in the maintenance of thiol-disulphide balance and interconversion by subjecting it to thiol stress. Protein profiles of samples subjected to thiol stress were compared with controls. One of the induced proteins was ‘CatalaseA’ as identified by MALDI-TOF and further confirmed by partial sequencing using LC/ESI-MS/MS. Measurement of catalase activity in stressed samples showed large increase supporting the structural identification. Disturbance in redox balance induces CatalaseA, to protect the bacterium from impending DNA damage mediated by hydrogen peroxide and hydroxyl radicals. Catalase seems to be a point of convergence for oxidative, reductive and thiol stresses.