Prof Magali Remaud-Simeon (Head of Enzyme Molecular Engineering group Toulouse Biotechnology Institute)
Thu 21 Nov 2019, 12:00 - 13:00
C.H Waddington Building, Seminar room 1.08, King's Building's

If you have a question about this talk, please contact: Julie Fyffe (jfyffe)

Image for Evolving enzymes for innovation

Host: Dr Louise Horsfall

With the development of synthetic biology, the conception of new enzymes for enzyme-based processes, chemo-enzymatic cascades or novel metabolic pathways is a timely topic. Together with molecular evolution, structurally-guided protein engineering and computational design are powerful technologies opening new accesses to enzymes showing desired functions.

We propose to give an overview of our recent achievements in this field with a first focus on computational-aided engineering of a-retaining transglucosylases from glycoside-hydrolase family 13 and 70. These enzymes are sucrose-active enzymes. They naturally display a broad acceptor substrate promiscuity and transfer the glucosyl unit of sucrose onto various types of hydroxylated acceptors to produce polysaccharides, glucooligosaccharides or glucoconjugates varying in size, structures and, by consequence, physicochemical properties. To further extend their applications, we applied engineering strategies to generate novel transglucosylases working on unnatural oligosaccharide acceptors1,2, which were chemically protected to  integrate programmed chemo-enzymatic cascades. In this way, new routes for the development of various patterns of antigenic oligosaccharides could be proposed. Furthermore, engineering approaches were also exploited to produce structurally controlled polymers3  and glycoconjugates4, or develop hybrid processes mixing enzymatic and chemical steps to generate various series of glyco-copolymers.

Similar approaches were also applied to set up a new and artificial metabolic pathway dedicated to di-hydroxybutyrate production5, a precursor of a hydroxyl-analog of methionine. The conception of this new synthetic pathway was inspired by the natural E. coli pathway starting from aspartate and leading to homoserine and required computer-aided engineering of three template enzymes showing no or little activity on the targeted substrates. The pathway was successfully expressed in E. coli to produce di-hydroxybutyrate.

All together, these achievements illustrate the remarkable enzyme evolvability and the growing panel of engineering tools that we have in hand for innovation. The strategies and approaches developed within the frame of these various engineering programmes will be described and discussed with regards to the constraints imposed by integration in either chemo-enzymatic pathways or living organisms.

1.      A Vergès, et al, 2015 ACS Catal., 2015

2.      D. Daude et al., ACS Catal 2018

3.      M. Claverie et al, ACS Catal., 2017, Molina et al, ACS Catal, 2019

4.      Malbert et al, Scientific reports, 2018

5.      T. Walther et al, Nature Com, 2017