Heterologous overexpression of glucose dehydrogenase from the halophilic archaeon Haloferax mediterranei, an enzyme of the medium chain dehydrogenase/reductase family

The First gene encoding a glucose dehydrogenase (GDH) from a halophilic org anism has been sequenced. Amino acid sequence alignments of GDH from Halofe rax mediterranei show a high degree of homology with the thermoacidophilic GDHs and with other enzymes from the medium chain dehydrogenase/reductase f amily. Heterologous overexpression using the mesophilic organism Escherichi a roll as the host has been performed and the expression product was obtain ed as inclusion bodies. To obtain the halophilic enzyme in its native form refolding and reactivation in a saline environment were required. A pure an d highly concentrated sample of the enzyme was obtained using a purificatio n procedure based on the protein's halophilicity. This method may be useful as a general procedure for purifying other halophilic proteins From mesoph ilic hosts. (C) 2001 Federation of European Microbiological Societies. Publ ished by Elsevier Science B.V. All rights reserved.