| Miscellaneous/General: | Proteins of the small heat shock family (sHSP) function as holding chaperones. While the exact mechanism of chaperone action is unclear and dependent on the individual family member, all sHSPs bind to unfolded or partially folded substrates in an ATP-independent manner and prevent interaction and aggregation with other components in the cell which could have a deleterious impact on the organism. The sHSP mitigates aggregation until conditions for proper folding are achieved. This can occur either by delivery of the substrate to an active folding network like Hsp70 or Hsp60, or by removal of the stress conditions, which may allow the substrate to refold on its own.
sHSPs contain the alpha-crystallin domain fold, but are otherwise poorly conserved across species. They are capable of forming higher order complexes of identical subunits, which are thought to play a role in their biological activity as chaperones. Many organisms possess more than one type of sHSP, which can vary in the substrate specificity and the size of complexes formed. The stability of sHSPs from extremophilic species have potential for impacting biotechnology as stabilizing agents and folding assistants.
Pyrococcus furiosus is a sulfur-reducing, strictly anaerobic, hyperthermophilic archaeon that displays optimal growth at 100C and a pH of 7.0. P. furiosus can grow in the absence of elemental sulfure, fermenting simple and complex carbohydrates and producing hydrogen and carbon dioxide end-products. |