Crystal Structure of DsbA from Corynebacterium diphtheriae and Its Functional Implications for CueP in Gram-Positive Bacteria |
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Authors: | Si-Hyeon Um Jin-Sik Kim Saemee Song Nam Ah Kim Seong Hoon Jeong Nam-Chul Ha |
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Affiliation: | 1.Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, Center for Food and Bioconvergence, Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul 151-921, Korea;2.College of Pharmacy, Dongguk University-Seoul, Goyang 410-820, Korea |
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Abstract: | In Gram-negative bacteria in the periplasmic space, the dimeric thioredoxin-fold protein DsbC isomerizes and reduces incorrect disulfide bonds of unfolded proteins, while the monomeric thioredoxin-fold protein DsbA introduces disulfide bonds in folding proteins. In the Gram-negative bacteria Salmonella enterica serovar Typhimurium, the reduced form of CueP scavenges the production of hydroxyl radicals in the copper-mediated Fenton reaction, and DsbC is responsible for keeping CueP in the reduced, active form. Some DsbA proteins fulfill the functions of DsbCs, which are not present in Gram-positive bacteria. In this study, we identified a DsbA homologous protein (CdDsbA) in the Corynebacterium diphtheriae genome and determined its crystal structure in the reduced condition at 1.5 Å resolution. CdDsbA consists of a monomeric thioredoxin-like fold with an inserted helical domain and unique N-terminal extended region. We confirmed that CdDsbA has disulfide bond isomerase/reductase activity, and we present evidence that the N-terminal extended region is not required for this activity and folding of the core DsbA-like domain. Furthermore, we found that CdDsbA could reduce CueP from C. diphtheriae. |
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Keywords: | CueP disulfide DsbA gram-positive bacteria |
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