Cloning and expression of an alpha-amylase encoding gene from the hyperthermophilic archaebacterium Thermococcus hydrothermalis and biochemical characterisation of the recombinant enzyme

An alpha-amylase encoding gene from the extremely thermophilic Archaea Ther mococcus hydrothermalis was cloned and expressed in Escherichia coli. The e ncoded alpha-amylase possesses molecular characteristics specific to the Ar chaea, especially from Pyrococcus species, with biochemical characteristics of the alpha-amylases from Thermococcus. The gene is 1374 bp long and enco des a protein of 457 amino acids composed of a 22 amino acid putative signa l peptide and a 435 amino acid mature protein (calculated molecular mass 49 236 Da). The T. hydrothermalis recombinant alpha-amylase is optimally acti ve at 75-85 degrees C and at pH 5.0-5.5. (C) 2000 Federation of European Mi crobiological Societies. Published by Elsevier Science B.V. All rights rese rved.