Wei Nian, Hu Lili, Song Lirong, Gan Nanqin
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Toxins (Basel). 2016 Oct 12;8(10):293. doi: 10.3390/toxins8100293.
Micocystin (MC) exists in cells in two different forms, free and protein-bound. We examined the dynamic change in extracellular free MCs, intracellular free MCs and protein-bound MCs in both batch cultures and semi-continuous cultures, using high performance liquid chromatography and Western blot. The results showed that the free MC per cell remained constant, while the quantity of protein-bound MCs increased with the growth of cells in both kinds of culture. Significant changes in the dominant MC-bound proteins occurred in the late exponential growth phase of batch cultures, while the dominant MC-bound proteins in semi-continuous cultures remained the same. In field samples collected at different months in Lake Taihu, the dominant MC-bound proteins were shown to be similar, but the amount of protein-bound MC varied and correlated with the intracellular MC content. We identified MC-bound proteins by two-dimensional electrophoresis immunoblots and mass spectrometry. The 60 kDa chaperonin GroEL was a prominent MC-bound protein. Three essential glycolytic enzymes and ATP synthase alpha subunit were also major targets of MC-binding, which might contribute to sustained growth in semi-continuous culture. Our results indicate that protein-bound MC may be important for sustaining growth and adaptation of sp.
微囊藻毒素（MC）在细胞内以两种不同形式存在，即游离态和与蛋白质结合态。我们使用高效液相色谱法和蛋白质印迹法，研究了分批培养和半连续培养中细胞外游离MC、细胞内游离MC和与蛋白质结合的MC的动态变化。结果表明，在两种培养方式中，每个细胞的游离MC含量保持恒定，而与蛋白质结合的MC量随着细胞生长而增加。在分批培养的指数生长后期，与MC结合的主要蛋白质发生了显著变化，而半连续培养中与MC结合的主要蛋白质保持不变。在太湖不同月份采集的野外样本中，与MC结合的主要蛋白质相似，但与蛋白质结合的MC量有所不同，且与细胞内MC含量相关。我们通过二维电泳免疫印迹和质谱法鉴定了与MC结合的蛋白质。60 kDa伴侣蛋白GroEL是一种突出的与MC结合的蛋白质。三种关键糖酵解酶和ATP合酶α亚基也是MC结合的主要靶点，这可能有助于半连续培养中的持续生长。我们的结果表明，与蛋白质结合的MC可能对维持生长和适应[具体物种名称]很重要。
