Recombinant protein expression in Sulfolobus islandicus

Since its invention, recombinant protein expression has greatly facilitated our understanding of various cellular processes in different biological systems because theoretically this technique renders any gene to be expressed in a mesophilic host like Escherichia coli, thus allowing functional characterizations of proteins of interest. However, such a practice has only yielded a limited success for proteins encoded in thermophilic archaea since thermophilic proteins are often present in an insoluble form when expressed in E. coli. As a result, it is advantageous to express recombinant proteins of thermophilic archaea in a homologous host, allowing a native form of recombinant protein to be purified and characterized. Here we present a detailed protocol for the homologous expression and purification of proteins in the thermophilic archaeon, Sulfolobus islandicus Rey15A.