Natrialba

Natrialba is a genus of archaeans in the family Natrialbaceae. The genus consists of many diverse species that can survive extreme environmental niches, especially they are capable to live in the waters saturated or nearly saturated with salt (halophiles). They have certain adaptations to live within their salty environments. For example, their cellular machinery is adapted to high salt concentrations by having charged amino acids on their surfaces, allowing the cell to keep its water molecules around these components. The osmotic pressure and these amino acids help to control the amount of salt within the cell.

For instance, N. magadii is an aerobic chemoorganotrophic, dual extremophile requiring alkaline conditions and hypersalinity for optimal growth. Those harsh conditions resulted in changed composition of charged amino acids in the proteins (average isoelectric point is only 4.64, whereas other organisms average is 6.5) with almost all proteins being highly acidic. The genome of N. magadii consists of four replicons with a total sequence of 4,443,643 bp and encodes 4,212 putative proteins. The genome analysis identified multiple genes coding putative proteins involved in adaptation to hypersalinity, stress response, glycosylation, and polysaccharide biosynthesis. Additionally, proton-driven ATP synthase and a variety of putative cytochromes and other proteins required for aerobic respiration and electron transfer had been found. The genome encodes a number of putative proteases/peptidases.