Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 106, Taiwan.
J Proteome Res. 2012 Nov 2;11(11):5362-75. doi: 10.1021/pr300582p. Epub 2012 Oct 15.
Rhodopseudomonas palustris (R. palustris) is a purple nonsulfur anoxygenic phototrophic bacterium with metabolic versatility and is able to grow under photoheterotrophic and chemoheterotrophic states. It has uses in carbon management, carbon recycling, hydrogen generation, and lipid production; therefore, it has the potential for bioenergy production and biodegradation. This study is the first to identify the phosphoproteome of R. palustris including 100 phosphopeptides from 54 phosphoproteins and 74 phosphopeptides from 42 phosphoproteins in chemoheterotrophic and photoheterotrophic growth conditions, respectively. In the identified phosphoproteome, phosphorylation at the threonine residue, Thr487, of pyruvate phosphate dikinase (PPDK, RPA1051) was found to participate in the regulation of carbon metabolism. Here, we show that PPDK enzyme activity is higher in photoheterotrophic growth, with Thr487 phosphorylation as a possible mediator. Under the same photoheterotrophic conditions, R. palustris with overexpressed wild-type PPDK showed an enhanced accumulation of total lipids than those with mutant PPDK (T487V) form. This study reveals the role of the PPDK in the production of biodiesel material, lipid content, with threonyl-phosphorylation as one of the possible regulatory events during photoheterotrophic growth in R. palustris.
沼泽红假单胞菌（Rhodopseudomonas palustris）是一种紫色非硫非氧光养细菌，具有代谢多样性，能够在光异养和化异养状态下生长。它在碳管理、碳循环、氢气生成和脂质生产方面有应用；因此，它有用于生物能源生产和生物降解的潜力。本研究首次鉴定了沼泽红假单胞菌的磷酸蛋白质组，包括化异养和光异养生长条件下分别有 100 个磷酸肽来自 54 个磷酸化蛋白和 74 个磷酸肽来自 42 个磷酸化蛋白。在鉴定的磷酸蛋白质组中，发现了丙酮酸磷酸二激酶（PPDK，RPA1051）的 Thr487 残基磷酸化参与了碳代谢的调节。在这里，我们表明 PPDK 酶活性在光异养生长中更高，Thr487 磷酸化可能是一种介导。在相同的光异养条件下，过表达野生型 PPDK 的沼泽红假单胞菌比具有突变型 PPDK（T487V）形式的总脂质积累更高。本研究揭示了 PPDK 在生物柴油材料生产中的作用，脂质含量，Thr 磷酸化是沼泽红假单胞菌光异养生长中可能的调节事件之一。
