Inactivation of thioredoxin-like gene alters oxidative stress resistance and reduces cytochrome c oxidase activity in Agrobacterium tumefaciens.
Thioredoxin-like protein (TlpA) is a membrane-anchored periplasmic protein that contains a thioredoxin domain at its C-terminus. An Agrobacterium tumefaciens mutant lacking functional tlpA shows increased sensitivity to a superoxide generator, increased resistance to H2O2, and reduced cytochrome c oxidase activity. Whereas the levels of antioxidant enzymes, including total superoxide dismutase (SOD) and catalases, are unaltered, high expression of periplasmic SOD partially restores the superoxide hypersensitivity of the mutant, suggesting an accumulation of superoxide anions in the periplasm. The change in the ability of the mutant to cope with H2O2 stress is independent of OxyR, an H2O2 sensor and transcription regulator. The presented data indicate that TlpA not only is involved in the proper assembly of cytochrome c but is also implicated in the bacterial oxidative stress response.
Tanboon
Weerachai
W
Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand.
Chuchue
Tatsanee
T
Vattanaviboon
Paiboon
P
Mongkolsuk
Skorn
S
D016960:Agrobacterium tumefaciens / Q000235:genetics / Q000502:physiology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D002374:Catalase / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000378:metabolism*; D055786:Gene Knockout Techniques; D006861:Hydrogen Peroxide / Q000494:pharmacology; D018384:Oxidative Stress; D013312:Stress, Physiological; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000494:pharmacology; D013879:Thioredoxins / Q000235:genetics / Q000502:physiology*
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D013481:Superoxides; D013879:Thioredoxins; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase; D003576:Electron Transport Complex IV