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Applied and Environmental Microbiology, June 2001, p. 2445-2452, Vol. 67, No. 6
Department of Material and Life
Science1 and Department of
Biotechnology,2 Graduate School of Engineering,
Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, and
Department of Synthetic Chemistry and Biological Chemistry,
Graduate School of Engineering, Kyoto University, Kyoto
606-8501,3 Japan
Received 29 December 2000/Accepted 16 March 2001
The gene encoding subtilisin-like protease T. kodakaraensis subtilisin was cloned from a hyperthermophilic
archaeon Thermococcus kodakaraensis KOD1. T. kodakaraensis subtilisin is a member of the subtilisin family and
composed of 422 amino acid residues with a molecular weight of 43,783. It consists of a putative presequence, prosequence, and catalytic
domain. Like bacterial subtilisins, T. kodakaraensis
subtilisin was overproduced in Escherichia coli in a form
with a putative prosequence in inclusion bodies, solubilized in the
presence of 8 M urea, and refolded and converted to an active molecule.
However, unlike bacterial subtilisins, in which the prosequence was
removed from the catalytic domain by autoprocessing upon refolding,
T. kodakaraensis subtilisin was refolded in a form with a
putative prosequence. This refolded protein of recombinant T. kodakaraensis subtilisin which is composed of 398 amino acid residues (Gly
0099-2240/01/$04.00+0 DOI: 10.1128/AEM.67.6.2445-2452.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Active Subtilisin-Like Protease from a
Hyperthermophilic Archaeon in a Form with a Putative
Prosequence
82 to Gly316), was purified to
give a single band on a sodium dodecyl sulfate (SDS)-polyacrylamide gel
and characterized for biochemical and enzymatic properties. The good
agreement of the molecular weights estimated by SDS-polyacrylamide gel
electrophoresis (44,000) and gel filtration (40,000) suggests that
T. kodakaraensis subtilisin exists in a monomeric form.
T. kodakaraensis subtilisin hydrolyzed the synthetic
substrate
N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide only
in the presence of the Ca2+ ion with an optimal pH and
temperature of pH 9.5 and 80°C. Like bacterial subtilisins, it showed
a broad substrate specificity, with a preference for aromatic or large
nonpolar P1 substrate residues. However, it was much more stable than
bacterial subtilisins against heat inactivation and lost activity with
half-lives of >60 min at 80°C, 20 min at 90°C, and 7 min at
100°C.
*
Corresponding author. Mailing address: Department of
Material and Life Science, Graduate School of Engineering, Osaka
University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan. Phone and fax:
81-(0)6-6879-7938. E-mail:
kanaya{at}ap.chem.eng.osaka-u.ac.jp
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