Stark Helge, Wolf Jacqueline, Albersmeier Andreas, Pham Trong K, Hofmann Julia D, Siebers Bettina, Kalinowski Jörn, Wright Phillip C, Neumann-Schaal Meina, Schomburg Dietmar
Department of Bioinformatics and Biochemistry, Technische Universität Braunschweig, Germany.
Center for Biotechnology - CeBiTec, Universität Bielefeld, Germany.
FEBS J. 2017 Jul;284(13):2078-2095. doi: 10.1111/febs.14105. Epub 2017 May 29.
The thermoacidophilic Crenarchaeon Sulfolobus solfataricus is a model organism for archaeal adaptation to extreme environments and renowned for its ability to degrade a broad variety of substrates. It has been well characterised concerning the utilisation of numerous carbohydrates as carbon source. However, its amino acid metabolism, especially the degradation of single amino acids, is not as well understood. In this work, we performed metabolic modelling as well as metabolome, transcriptome and proteome analysis on cells grown on caseinhydrolysate as carbon source in order to draw a comprehensive picture of amino acid metabolism in S. solfataricus P2. We found that 10 out of 16 detectable amino acids are imported from the growth medium. Overall, uptake of glutamate, methionine, leucine, phenylalanine and isoleucine was the highest of all observed amino acids. Our simulations predict an incomplete degradation of leucine and tyrosine to organic acids, and in accordance with this, we detected the export of branched-chain and aromatic organic acids as well as amino acids, ammonium and trehalose into the culture supernatants. The branched-chain amino acids as well as phenylalanine and tyrosine are degraded to organic acids via oxidative Stickland reactions. Such reactions are known for prokaryotes capable of anaerobic growth, but so far have never been observed in an obligate aerobe. Also, 3-methyl-2-butenoate and 2-methyl-2-butenoate are for the first time found as products of modified Stickland reactions for the degradation of branched-chain amino acids. This work presents the first detailed description of branched-chain and aromatic amino acid catabolism in S. solfataricus.
嗜热嗜酸的泉古菌嗜热栖热菌是古菌适应极端环境的模式生物，以其降解多种底物的能力而闻名。关于其利用多种碳水化合物作为碳源的情况已有充分的表征。然而，其氨基酸代谢，尤其是单个氨基酸的降解，尚未得到很好的理解。在这项工作中，我们对以酪蛋白水解物作为碳源生长的细胞进行了代谢建模以及代谢组、转录组和蛋白质组分析，以便全面了解嗜热栖热菌P2中的氨基酸代谢。我们发现，在16种可检测到的氨基酸中，有10种是从生长培养基中导入的。总体而言，谷氨酸、蛋氨酸、亮氨酸、苯丙氨酸和异亮氨酸的摄取量在所有观察到的氨基酸中是最高的。我们的模拟预测亮氨酸和酪氨酸不完全降解为有机酸，与此一致的是，我们检测到支链和芳香族有机酸以及氨基酸、铵和海藻糖分泌到培养上清液中。支链氨基酸以及苯丙氨酸和酪氨酸通过氧化斯特克兰德反应降解为有机酸。这种反应在能够厌氧生长的原核生物中是已知的，但迄今为止从未在专性需氧菌中观察到。此外，首次发现3 - 甲基 - 2 - 丁烯酸和2 - 甲基 - 2 - 丁烯酸是支链氨基酸降解的修饰斯特克兰德反应的产物。这项工作首次详细描述了嗜热栖热菌中支链和芳香族氨基酸的分解代谢。
