Crossing the Border: From Keto- to Imine Reduction in Short-Chain Dehydrogenases/Reductases |
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Authors: | Sebastian Roth Peter Stockinger Jakob Steff Simon Steimle Dr Viktor Sautner Prof Dr Kai Tittmann Prof Dr Jürgen Pleiss Prof Dr Michael Müller |
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Affiliation: | 1. Institute of Pharmaceutical Sciences, University of Freiburg, Albertstrasse 25, 79104 Freiburg, Germany;2. Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, Allmandring 31, 70569 Stuttgart, Germany;3. Department of Molecular Enzymology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany |
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Abstract: | The family of NAD(P)H-dependent short-chain dehydrogenases/reductases (SDRs) comprises numerous biocatalysts capable of C=O or C=C reduction. The highly homologous noroxomaritidine reductase (NR) from Narcissus sp. aff. pseudonarcissus and Zt_SDR from Zephyranthes treatiae, however, are SDRs with an extended imine substrate scope. Comparison with a similar SDR from Asparagus officinalis (Ao_SDR) exhibiting keto-reducing activity, yet negligible imine-reducing capability, and mining the Short-Chain Dehydrogenase/Reductase Engineering Database indicated that NR and Zt_SDR possess a unique active-site composition among SDRs. Adapting the active site of Ao_SDR accordingly improved its imine-reducing capability. By applying the same strategy, an unrelated SDR from Methylobacterium sp. 77 (M77_SDR) with distinct keto-reducing activity was engineered into a promiscuous enzyme with imine-reducing activity, thereby confirming that the ability to reduce imines can be rationally introduced into members of the “classical” SDR enzyme family. Thus, members of the SDR family could be a promising starting point for protein approaches to generate new imine-reducing enzymes. |
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Keywords: | asymmetric reduction biocatalysis enzyme mutagenesis rational design |
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