A NADPH-dependent (S)-imine reductase (SIR) from Streptomyces sp GF3546 for asymmetric synthesis of optically active amines: purification, characterization, gene cloning, and expression

作者：Mitsukura Koichi^*; Kuramoto Tatsuya; Yoshida Toyokazu; Kimoto Norihiro; Yamamoto Hiroaki; Nagasawa Toru

来源：Applied Microbiology and Biotechnology, 2013, 97(18): 8079-8086.

DOI：10.1007/s00253-012-4629-4

• Asymmetric reduction
• (S)-Imine reductase
• Streptomyces sp GF3546
• Optically active amine

A NADPH-dependent (S)-imine reductase (SIR) was purified to be homogeneous from the cell-free extract of Streptomyces sp. GF3546. SIR appeared to be a homodimer protein with subunits of 30.5 kDa based on SDS-polyacrylamide gel electrophoresis and HPLC gel filtration. It also catalyzed the (S)-enantioselective reduction of not only 2-methyl-1-pyrroline (2-MPN) but also 1-methyl-3,4-dihydroisoquinoline and 6,7-dimethoxy-1-methyl-3,4-dihydroisoquinoline. Specific activities for their imines were 130, 44, and 2.6 nmol min(-1) mg(-1), and their optical purities were 92.7 % ee, 96.4 % ee, and %26gt; 99 % ee, respectively. Using a NADPH-regenerating system, 10 mM 2-MPN was converted to amine with 100 % conversion and 92 % ee after 24 h. The amino acid sequence analysis revealed that SIR showed about 60 % identity to 6-phosphogluconate dehydrogenase. However, it showed only 37 % identity with Streptomyces sp. GF3587 (R)-imine reductase. Expression of SIR in Escherichia coli was achieved, and specific activity of the cell-free extract was about two times higher than that of the cell-free extract of Streptomyces sp. GF3546.

• 出版日期2013-9