Caratterizzazione strutturale del sistema redox Tioredossina/Tioredossina Reduttasi dall'archaeon Sulfolobus solfataricus

Recent investigations have demonstrated that disulfide bridges may play a crucial role in the stabilization of proteins in hyperthermophilic organisms. The process of disulfide formation is not spontaneous but it is modulated by complex enzymatic systems. A major role in this process is played by ubiquitous proteins belonging to the thioredoxin superfamily, which includes enzymes such as thioredoxins (Trx), thioredoxin reductases (TrxR), and disulfide oxidases/isomerases. Here we report a characterization of the structure and stability of the TrxR (SsTrxRB3) isolated from Sulfolobus solfataricus. This protein is particularly interesting since it able to process different substrates (Trx and PDO) and it is endowed with an additional NADH oxidase activity. Although some characterizations of TrxR isolated from eubacteria have been reported, no structural information has been hitherto for the archeal counterparts.