WblA Response to Oxidative Stress and Its Putative Interaction with SCO2553 Protein in Streptomyces coelicolor

초록

Previously, we identified and characterized a novel global antibiotic down-regulator named a whiB-like gene A (wblA, SCO3579) in Streptomyces coelicolor and several other Streptomyces species. Recently, a WblA orthologue named WhcA in Corynebacterium glutamicum, a high G+C Gram-positive bacterium belonging to actinomycetes, was found to play a negative role in oxidative stress response. Moreover, WhcA was further confirmed to interact with dioxygenase-encoding SpiA (stress protein interacting with WhcA) in C. glutamicum. Based on high homoloy between WblA and WhcA, S. coelicolor wblA is proposed to play a similar response to oxidative stress, and to interact with SpiA orthogue protein (SCO2553 protein) in S. coelicolor. Using real-time RT-PCR analysis, we compared the transcription levels of oxidative stress related genes including sodF (superoxide dismutase), sodF2 (superoxide dismutase Fe-Zn), sodN (superoxide dismutase), trxB (thioredoxin reductase NADPH), trxB2 (thioredoxin reductase) between S. coelicolor wild-type and a wblA mutant in the presence or absence of oxidative stress. Like WhcA-mediated oxidative response in C. glutamicum, WblA plays a similar negative role in oxidative stress response in S. coelicolor. Furthermore, a specific in vitro interaction between WblA and SCO2553 protein, which are individually expressed and purified in E. coli, is also observed. More detailed results will be further discussed.