Molecular Biology Division, Bhabha Atomic Research Center, Mumbai 400085, India.
J Proteomics. 2010 Mar 10;73(5):976-91. doi: 10.1016/j.jprot.2009.12.011. Epub 2010 Jan 6.
Cell-free extracts of Synechocystis 6803 were fractionated by successive ultracentrifugation at 40,000 x g, 90,000 x g and 150,000 x g to obtain the three thylakoid fractions designated as 40k, 90k and 150k fractions respectively. These fractions showed differences in absorption and emission spectra. Nano-LC-ESI-Q-TOF MS analysis identified 123 proteins belonging to membrane as well as cytosolic fraction. Out of these proteins, there were 22 proteins with transmembrane helices and 12 proteins with signal peptide. There were 77 proteins common across all the three fractions. Most of these proteins were subunits of photosynthetic complexes, CF(0)-CF(1) ATP synthase or ribosomal proteins. Among the rest of the proteins, 8 were exclusive to 40k fraction, 3 were exclusive to 90k fraction and 13 were exclusive to 150k fraction. There were 10 proteins common between 40k and 90k fractions and 12 proteins common between 90k and 150k fractions. There were no common proteins detected between 40k and 150 fractions. The results suggested existence of heterogeneity in thylakoids of Synechocystis 6803, which may lead to micro-compartmentation and functional heterogeneity in the thylakoids of this organism as seen previously.
将聚球藻 6803 的无细胞提取物分别经 40000xg、90000xg 和 150000xg 连续超速离心，得到三个命名为 40k、90k 和 150k 的类囊体 fractions。这些 fractions 在吸收和发射光谱上表现出差异。纳升 LC-ESI-Q-TOF MS 分析鉴定出 123 种属于膜和胞质 fraction 的蛋白质。在这些蛋白质中，有 22 种具有跨膜螺旋，12 种具有信号肽。有 77 种蛋白质存在于所有三个 fractions 中。这些蛋白质大多是光合复合物、CF(0)-CF(1)ATP 合酶或核糖体蛋白质的亚基。在其余的蛋白质中，8 种蛋白质 exclusive 于 40k fraction，3 种 exclusive 于 90k fraction，13 种 exclusive 于 150k fraction。有 10 种蛋白质存在于 40k 和 90k fractions 之间，12 种蛋白质存在于 90k 和 150k fractions 之间。在 40k 和 150 fractions 之间没有检测到 common 蛋白质。结果表明聚球藻 6803 的类囊体存在异质性，这可能导致该生物的类囊体出现 micro-compartmentation 和功能异质性，如先前所见。
