SHIMADA Hiroaki Science University of Tokyo, Dept.of Biological Science and Technology, Associate Professor, 基礎工学部, 助教授 (70281748)
TAGUCHI Seiichi Science University of Tokyo, Dept.of Biological Science and Technology, Research Associate, 基礎工学部, 助手 (70216828)
|Budget Amount *help
¥1,500,000 (Direct Cost : ¥1,500,000)
Fiscal Year 1999 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1998 : ¥700,000 (Direct Cost : ¥700,000)
We have, so far, obtained a variety of cold-adapted proteases from a mesophilic serine protease, subtilisin BPN', by means of evolutionary engineering. In 1998, we focused our attention to a mutation point of G131D in m-63, one of these evolvants, and random amino acid substitution was carried out for this point. Among 19 amino acid substitutions, Phe gave the highest activity. A mutation scrambling system was constructed, in the same year, for combining various mutations selected as those contributed to the cold adaptation. In 1999, DNA shuffling system was also constructed. Using these evolutionary systems, besides random mutagenesis, we will be able to increase the possibility of evolution toward cold adaptation. Finally, we applied our experimental evolution system also to α-amylase, one of industrially important enzymes other than protease. As the result, several cold-adapted α-amylase evolvants were obtained. This indicates that our system so far constructed were universally useful not only for cold adaptation of proteases, but also for that of other industrially and environmentally important enzymes.