Genome mining and characterisation of a novel transaminase with remote stereoselectivity

D P Gavin,P O’Neill,A M Foley,A R Maguire,M Schwarz,D F Woods,F J Reen,P A Sánchez-Murcia,F O’Gara,I Abreu-Castilla,J Rocha-Martin

doi:10.1038/s41598-019-56612-7

Abstract

Microbial enzymes from pristine niches can potentially deliver disruptive opportunities in synthetic routes to Active Pharmaceutical Ingredients and intermediates in the Pharmaceutical Industry. Advances in green chemistry technologies and the importance of stereochemical control, further underscores the application of enzyme-based solutions in chemical synthesis. The rich tapestry of microbial diversity in the oceanic ecosystem encodes a capacity for novel biotransformations arising from the chemical complexity of this largely unexplored bioactive reservoir. Here we report a novel ω-transaminase discovered in a marine sponge Pseudovibrio sp. isolate. Remote stereoselection using a transaminase has been demonstrated for the first time using this novel protein. Application to the resolution of an intermediate in the synthesis of sertraline highlights the synthetic potential of this novel biocatalyst discovered through genomic mining. Integrated chemico-genomics revealed a unique substrate profile, while molecular modelling provided structural insights into this ‘first in class’ selectivity at a remote chiral centre.

Highlights

Microbial enzymes from pristine niches can potentially deliver disruptive opportunities in synthetic routes to Active Pharmaceutical Ingredients and intermediates in the Pharmaceutical Industry
Many elegant biocatalytic routes to chiral amines have been reported utilising a range of enzymatic families, including hydrolases, monoamine oxidases, imine reductases and reductive aminases in the kinetic resolution and asymmetric synthesis of pharmaceutical intermediates[10,11,12,13,14,15,16,17,18,19,20]
Having envisioned a transaminase-mediated resolution of the sertraline intermediate (Fig. 2a) and inspired by the elegant work of Bornscheuer and co-workers on transaminase evolution towards bulky substrates[49], we set about the task of finding a transaminase with synthetically useful activity towards interconversion of 1 and 8b

Summary

Introduction

It is becoming increasingly apparent that the functional novelty encoded within the rich genetic diversity of marine polymicrobial communities extends to the enzymatic activities that sustain microbial life in this ecosystem While technologies such as directed evolution and rational design have provided further added value to existing enzyme frameworks, identifying source proteins with novel functionality has several benefits, where previously pristine niches have revealed their rich and biodiverse bioactive potential[31]. Accessing culturable microbes from marine sponges remains challenging, several species have emerged with interesting bioactive and biosynthetic profiles They are an untapped source of proteins with novel favourable functionality and/or substrate scope based on the unique biotransformations required of them e.g. accessing halogenated metabolites. These enzymes could be expected to exhibit additional properties such as salt and osmotic tolerance offering robustness in synthetic bioreactor pipelines[31,32]

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Results

Discussion

Conclusion