RT Journal
A1 Falb, Michaela
A1 Pfeiffer, Friedhelm
A1 Palm, Peter
A1 Rodewald, Karin
A1 Hickmann, Volker
A1 Tittor, Jörg
A1 Oesterhelt, Dieter
T1 Living with two extremes: Conclusions from the genome sequence of Natronomonas pharaonis
JF Genome Research 
JO Genome Research 
YR 2005 
FD October 01 
VO 15 
IS 10 
SP 1336 
OP 1343 
DO 10.1101/gr.3952905 
UL http://genome.cshlp.org/content/15/10/1336.abstract 
AB Natronomonas pharaonis is an extremely haloalkaliphilic archaeon that was isolated from salt-saturated lakes of pH 11. 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.