Cloning of an alpha-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 als o in eukaryotes and bacteria. The gene encoding the enzyme was cloned from Thermococcus hydrothermalis by complementation of a Saccharomyces cerevisia e deficiency maltase mutant strain. The gDNA clone isolated encodes an open reading frame corresponding to a protein of 242 amino acids. The protein s hows 42% identity to a Pyrococcus horikoshii unknown ORF but no similaritie s were obtained with polysaccharidase sequences. (C) 1999 Federation of Eur opean Biochemical Societies.