title: Borrelia burgdorferi bb0728 encodes a coenzyme A disulphide reductase whose function suggests a role in intracellular redox and the oxidative stress response.
abstract: The cellular responses of Borrelia burgdorferiTo reactive oxygen species (ROS) encountered during the different stages of its infective cycle are poorly understood. Few enzymes responsible for protecting proteins, DNA/RNA and lipids from damage by ROS have been identified and characterized. Data presented here suggest that bb0728 encodes an enzyme involved in this process. Biochemical analyses on purified recombinant BB0728 indicated that it functioned as a coenzyme A disulphide reductase (CoADR) (specific activity approximately 26 units per mg of protein). This enzyme was specific for coenzyme A (CoA) disulphide, required NADH and had no significant activity against other disulphides, such as oxidized glutathione or thioredoxin. The high intracellular concentration of reduced CoA (CoASH) in B. burgdorferi cells ( approximately 1 mM) and absence of glutathione suggest that CoA is the major low-molecular-weight thiol in this spirochete. Interestingly, CoASH was able to reduce H(2)O(2) and be regenerated by CoADR suggesting one role for the system may be to protect B. burgdorferi from ROS. Further, mobility-shift assays and transcriptional fusion data indicated that bb0728 was positively regulated by the Borrelia oxidative stress response regulator, BosR. Taken together, these data suggest a role for BB0728 in intracellular redox and the oxidative stress response in B. burgdorferi.
authors.affiliation: Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Boylan
authors.forename: Charles S
authors.initials: CS
authors.lastname: Hummel
authors.forename: Stéphane
authors.initials: S
authors.lastname: Benoit
authors.forename: Jorge
authors.initials: J
authors.lastname: Garcia-Lara
authors.forename: Jennifer
authors.initials: J
authors.lastname: Treglown-Downey
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Crane
authors.forename: Frank C
authors.initials: FC
authors.lastname: Gherardini
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D025065:Borrelia burgdorferi / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D003065:Coenzyme A / Q000378:metabolism*; D017931:DNA Primers; D005798:Genes, Bacterial; D006861:Hydrogen Peroxide / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016366:Open Reading Frames; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010088:Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
chemical_list: D017931:DNA Primers; C017145:coenzyme A disulfide; D006861:Hydrogen Peroxide; D010088:Oxidoreductases; D003065:Coenzyme A