THERMOSTABLE BETA-GLYCOSIDASE FROM SULFOLOBUS-SOLFATARICUS

The Sulfolobus solfataricus beta-glycosidase (S beta gly) is a thermos table and thermophilic glycosyl-hydrolase with broad substrate specifi city. The enzyme hydrolizes beta-D-gluco-, fuco-, and galactosides, an d a large number of beta-linked glycoside dimers and oligomers, linked beta 1-3, beta 1-4, and beta 1-6, It is able to hydrolize oligosaccha rides with up to 5 glucose residues. Furthermore, it is also able to p romote transglycosylation reactions. The corresponding gene has been c loned and overexpressed both in yeast and Escherichia coli. Based on s equence acid functional data, the S beta gly has been assigned to the so-called EGA family of glycosyl-hydrolases, including beta-glycosidas es, beta-galactosidases and phosho-beta-galactosidases from mesophilic and thermophilic organisms of the three domains. The S beta gly has b een crystallized and the resolution of its structure is in progress. B ecause of its special properties, the enzymes has considerable biotech nological potential.