Cloning of an α-glucosidase gene from Thermococcus hydrothermalis by functional complementation of a Saccharomyces cerevisiae mal11n mutant strain

alpha-Glucosidase is found in methanogenic and thermophilic archaea and also in eukaryotes and bacteria. The gene encoding the enzyme was cloned from Thermococcus hydrothermalis by complementation of a Saccharomyces cerevisiae deficiency maltase mutant strain. The gDNA clone isolated encodes an open reading frame corresponding to a protein of 242 amino acids. The protein shows 42% identity to a Pyrococcus horikoshii unknown ORF but no similarities were obtained with polysaccharidase sequences. (C) 1999 Federation of European Biochemical Societies.