Living with two extremes:: Conclusions from the genome sequence of Natronomonas pharaonis
Living with two extremes:: Conclusions from the genome sequence of Natronomonas pharaonis
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DOI：
10.1101/gr.3952905
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发表时间：
2005-10-01
期刊：
影响因子：
7
通讯作者：
Oesterhelt, D
中科院分区：
文献类型：
--
作者：
Falb, M;Pfeiffer, F;Oesterhelt, D
嗜盐古菌（Natronomonaspharaonis）是一种极端嗜卤碱性古菌，从pH为II的盐饱和湖泊中分离出来。我们测序了其2.6-Mb富含GC的染色体和两个质粒（131和23 kb）。基因组分析表明，它适应于应对在高pH值下出现的严重氨和重金属缺乏症。高度的营养自给自足的预测和确认的增长在基本培养基中含有亮氨酸，但没有其他氨基酸或维生素。呼吸链复合物III类似物的基因在N. pharaonis基因组，但呼吸和氧化磷酸化实验证明。这些研究确定质子作为呼吸链和ATP合酶之间的耦合离子，与其他使用钠的嗜碱菌相反。分泌组分析预测了许多细胞外蛋白与耐碱脂质锚，这主要是通过双精氨酸途径出口。此外，多种糖基化的细胞表面蛋白可能形成保护性的复合细胞包膜。n. pharaonis完全具备古细菌信号转导和运动基因。几个受体/传感器信号鞭毛电机显示新的结构域架构。在盐古菌基因组中，信号转导基因簇发生重排，而参与信息处理或能量代谢的基因簇则表现出高度保守的基因顺序。
Natronomonas pharaonis is an extremely haloalkaliphilic archaeon that was isolated from salt-saturated lakes of pH II. We sequenced its 2.6-Mb GC-rich chromosome and two plasmids (131 and 23 kb). Genome analysis suggests that it is adapted to cope with severe ammonia and heavy metal deficiencies that arise at high pH values. A high degree of nutritional self-sufficiency was predicted and confirmed by growth in a minimal medium containing leucine but no other amino acids or vitamins. Genes for a complex III analog of the respiratory chain could not be identified in the N. pharaonis genome, but respiration and oxidative phosphorylation were experimentally proven. These studies identified protons as coupling ion between respiratory chain and ATP synthase, in contrast to other alkaliphiles using sodium instead. Secretome analysis predicts many extracellular proteins with alkaline-resistant lipid anchors, which are predominantly exported through the twin-arginine pathway. In addition, a variety of glycosylated cell surface proteins probably form a protective complex cell envelope. N. pharaonis is fully equipped with archaeal signal transduction and motility genes. Several receptors/transducers signaling to the flagellar motor display novel domain architectures. Clusters of signal transduction genes are rearranged in haloarchaeal genomes, whereas those involved in information processing or energy metabolism show a highly conserved gene order.