초록
<P>Optically pure 1,2-amino alcohols are highly valuable products as intermediates for chiral pharmaceutical products. Here we designed an environmentally friendly non-natural biocatalytic cascade for efficient synthesis of 1,2-amino alcohols from cheaper epoxides. A redesignated ω-transaminase PAKω-TA was tested and showed good bioactivity at a lower pH than other reported transaminases. The cascade was efficiently constructed as a single one-pot <I>E. coli</I> recombinant, by coupling SpEH (epoxide hydrolase), MnADH (alcohol dehydrogenase), and PAKω-TA. Furthermore, RBS regulation strategy was used to overcome the rate limiting step by increasing expression of MnADH. For cofactor regeneration and amino donor source, an interesting point was involved as that a cofactor self-sufficient system was designed by expression of GluDH. It established a “bridge” between the cofactor and the cosubstrate, such that the cofactor self-sufficient system could release cofactor (NADP<SUP>+</SUP>) and cosubstrate (<SMALL>L</SMALL>-Glutamine) regenerated simultaneously. The recombinant <I>E. coli</I> BL21 (SGMP) with cofactor self-sufficient whole-cell cascade biocatalysis showed high ee value (>99%) and high yield, with 99.6% conversion of epoxide (<I>S</I>)-<B>1a</B> to 1,2-amino alcohol (<I>S</I>)-<B>1d</B> in 10 h. It further converted (<I>S</I>)-<B>2a</B>-<B>5a</B> to (<I>S</I>)-<B>2d</B>-<B>5d</B> with varying conversion rates ranging between 65-96.4%. This study first provides one-step synthesis of optically pure 1,2-amino alcohols from (<I>S</I>)-epoxides employing a synthetic redox-self-sufficient cascade.</P><BR>[FIG OMISSION]</BR>