大腸菌体内で不活性型として生産される超好熱アーキア由来リコンビナント酵素の機能・構造解析

抄録

Several enzymes containing glutamate dehydrogenase from hyperthermophiles have been reported to be expressed as inactive forms in a mesophile Escherichia coli. We have recently found that the recombinant Pyrobaculum islandicum glutamate dehydrogenase（Pis-GDH）expressed in E. coli hardly exhibits the activity, and that the heat treatment dramatically activated the inactive enzyme to the activity level comparable to that of the native enzyme. This review focuses mainly on the structural changes of the Pis-GDH in heat activation measured by small-angle X-ray scattering, differential scanning calorimetry, circular dichroism, and fluorescence spectrum in the presence of 8-anilinonaphthalene-1-sulfonate. In addition, we describe the hyperthermophilic homoserine dehydrogenase showing unique coenzyme preference as other type of the inactive recombinant enzyme. This may be informative for the better production of active recombinant enzymes from hyperthermophiles.