Silicon Cell Model for the central carbohydrate metabolism of the archaeon Sulfolobus solfataricus under temperature variation

Since their discovery as a third domain of life, Archaea represent an important comparative lineage to study the evolution and characteristics of central cellular functions in all living cells. Archaea have gained special interest, because mechanisms involved in information processing (transcription, translation, replication, etc.) represent a simpler version of eukaryotic equivalents and because Archaea harbor several unique metabolic features. The archaeal central carbohydrate metabolism is characterized by unusual pathways and enzymes many of which differ from the bacterial or eukaryotic counterparts (Siebers & Schönheit 2005). However, although pathways for hexose metabolism have been unraveled in several Archaea, their regulation as well as energetics is still not understood.

The archaeal model organism of choice for a systems biology approach isSulfolobus solfataricus, a thermoacidophilic Crenarchaeon that grows ataround 80°C and pH 3 (Zillig et al. 1980). S. solfataricus uses anunusual branched Entner-Doudoroff (ED) pathway for glucose catabolism(Ahmed et al. 2005). Life at high temperature requires a very efficientadaptation to temperature changes, which is most difficult to deal withfor organisms and it is unclear how biological networks can withstandand respond to such changes. In the SulfoSYS project, within thetransnational SysMO initiative (http://www.sysmo.net/),10 European partners study the central carbohydrate metabolism (CCM),i.e. the branched ED pathway of S. solfataricus and its regulationunder temperature variation by the integration of genomic,transcriptomic, proteomic, metabolomic, kinetic and biochemicalinformation as well as modeling. The long term goal of the project isto build a sufficiently precise replica for this part of the livingcell “a Silicon Cell” to enable computation of life, particular itsrobustness to changes in temperature, at the system level (Albers etal. 2009).