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Enzymatic Synthesis of Polyesters: A QM/MM Study

preprint
revised on 06.01.2020 and posted on 07.01.2020 by Pedro Figueiredo, Beatriz C. Almeida, Daniel F.A.R. Dourado, Andreia F. Sousa, Armando J.D. Silvestre, Alexandra Carvalho
Plastic pollution is causing an immeasurable damage to marine and land eco-systems. Better alternatives are actively being sought-after, such as biodegradable polyesters obtained by enzymatic synthesis. However, wild type enzymes still pose fundamental efficiency limitations that can be circumvented by protein reengineering approaches.Here we compare in detail the catalytic mechanisms for polycaprolactone synthesis by the enzymes Archaeoglobus fulgidus carboxylesterase (AfEST) and Candida antarctica lipase B (CalB) by performing Quantum mechanics calculations and Quantum Mechanics/Molecular Mechanics Molecular Dynamics simulations. We found that bond forming/breaking events are concerted with proton transfer to or from the catalytic histidine in all the transition states, but with different degrees of coupling between the motions of the atoms involved. Our results give important insights towards the design of new enzyme variants combining good activity with high thermostability.

Funding

MIT-EXPL/ISF/0021/2017

IF/01272/2015

UID/NEU/04539/2019

UID/CTM/50011/2019

History

Email Address of Submitting Author

atpcarvalho@uc.pt

Institution

CNC, Coimbra University

Country

Portugal

ORCID For Submitting Author

0000-0003-2827-5527

Declaration of Conflict of Interest

No conflict of interest

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