Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
Lett Appl Microbiol. 2009 Dec;49(6):689-94. doi: 10.1111/j.1472-765X.2009.02727.x. Epub 2009 Aug 22.
To evaluate the antioxidant effect of carotenoids from Deinococcus radiodurans on protein.
Deinococcus radiodurans strain R1 (ATCC 13939) and its mutant strain R1DeltacrtB were used for this study. The total carotenoids (R1ex) from D. radiodurans were obtained by extraction with acetone/methanol (7 : 2, by vol), and their antioxidant activity was measured using the DPPH (2,2-diphenyl-1-picrylhydrazyl) system. The protein oxidation level, in vitro and in the cell, was measured using the DNPH (2,4-dinitrophenyl hydrazine) method. The carotenoid extract R1ex scavenged 40.2% DPPH radicals compared to beta-carotene (31.7%) at a concentration of 0.5 mg ml(-1). The intracellular level of protein oxidation in mutant R1DeltacrtB, which does not contain carotenoid, was 0.0212 mmol mg(-1) protein which is significantly greater than that in the wild type (0.0169 mmol mg(-1) protein) following the treatment with H(2)O(2). The purified major carotenoid product (deinoxanthin) from the wild type showed a greater inhibition of oxidative damage in bovine serum albumin than lycopene or lutein.
Carotenoids prevent protein oxidation and contribute to the resistance to cell damage in D. radiodurans.
Our results provide the evidence that carotenoids can protect proteins in D. radiodurans against oxidative stress.
评估来自耐辐射球菌的类胡萝卜素对蛋白质的抗氧化作用。
本研究使用耐辐射球菌菌株 R1（ATCC 13939）及其突变株 R1DeltacrtB。通过用丙酮/甲醇（7:2，体积比）提取获得耐辐射球菌的总类胡萝卜素（R1ex），并使用 DPPH（2,2-二苯基-1-苦肼基）系统测量其抗氧化活性。使用 DNPH（2,4-二硝基苯肼）法在体外和细胞内测量蛋白质氧化水平。类胡萝卜素提取物 R1ex 在 0.5mgml(-1)浓度下清除 40.2%DPPH 自由基，比β-胡萝卜素（31.7%）高。不含有类胡萝卜素的突变株 R1DeltacrtB 中的细胞内蛋白质氧化水平为 0.0212mmolmg(-1)蛋白质，这明显高于野生型（0.0169mmolmg(-1)蛋白质）在 H(2)O(2)处理后。从野生型中纯化的主要类胡萝卜素产物（脱氮叶黄素）对牛血清白蛋白的氧化损伤抑制作用大于番茄红素或叶黄素。
类胡萝卜素可防止蛋白质氧化，并有助于耐辐射球菌抵抗细胞损伤。
我们的结果提供了证据，表明类胡萝卜素可以保护耐辐射球菌中的蛋白质免受氧化应激。
