Knockout of crtB or crtI gene blocks the carotenoid biosynthetic pathway in Deinococcus radiodurans R1 and influences its resistance to oxidative DNA-damaging agents due to change of free radicals scavenging ability |
| |
Authors: | Zhang Lei Yang Qiao Luo Xuesong Fang Chengxiang Zhang Qiuju Tang Yali |
| |
Institution: | (1) College of Life Sciences, Wuhan University, Wuhan, 430072, People’s Republic of China |
| |
Abstract: | Deinococcus radiodurans R1, a red-pigmented strain of the extremely radioresistant genus Deinococcus, contains a major carotenoid namely deinoxanthin. The high resistance of this organism against the lethal actions of DNA-damaging
agents including ionizing radiation and ultraviolet light (UV) has been widely reported. However, the possible antioxidant
role of carotenoids in this strain has not been completely elucidated. In this study, we constructed two colorless mutants
by knockout of crtB and crtI genes, respectively. Comparative analysis of the two colorless mutants and the wild type showed that the two colorless mutants
were more sensitive to ionizing radiation, UV, and hydrogen peroxide, but not to mitomycin-C (MMC). With electron spin resonance
(ESR) and spin trapping techniques, we observed that hydroxyl radical signals occurred in the suspensions of UV irradiated
Deinococcus radiodurans cells and the intensity of signals was influenced by carotenoids levels. We further showed that the carotenoid extract from
the wild type could obviously scavenge superoxide anions generated by the irradiated riboflavin/EDTA system. These results
suggest that carotenoids in D. radiodurans R1 function as free radical scavengers to protect this organism against the deleterious effects of oxidative DNA-damaging
agents. |
| |
Keywords: | Deinococcus radiodurans Carotenoids ESR Free radical |
本文献已被 PubMed SpringerLink 等数据库收录! |
|