Enzyme Hydration: How to Retain Resistance in Ionic Liquids

  Haiyang Cui. Copyright: © biotec Haiyang "Ocean" Cui

Cui, H., Zhang, L., Eltoukhy, L., Markel, U., Jaeger, K. E., Schwaneberg, U., Davari, M. D., ACS Sustainable Chem. Eng. 2022, 10, 46, 15104–15114

Enzyme hydration determines the resistance of enzyme in ionic liquids

In the past decade, biocatalysis has made great strides. There is a compelling need for finding green and sustainable media for biocatalysis in the industry as the environment can be adversely affected by volatile organic solvents. Ionic liquids (ILs) potentially offer an alternative reaction media for enzyme-catalyzed syntheses with the reduced solvent evaporation and environmental burden, low flammability, and high recoverability. However, ILs as reaction media are often limited by poor enzymatic activity and stability in ILs. We printed a comprehensive IL–enzyme interaction map by studying 45 molecular observables of 30 lipase A from Bacillus subtilis (BSLA) variants in four ILs and a substitutional landscape with 1504 BSLA variants. The results demonstrated that the enzyme hydration shell is the deciding and independent factor determining the enzyme’s IL resistance. A universal positive correlation (up to R2 = 0.96 in 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIM][TfO]) and R2 = 0.85 in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl)) was verified, and an experimentally derived ranking of amino acid substitutions is summarized in a list to provide benefits for better protein engineering practice. Hydration-guided engineering yielded a supremely tolerant BSLA variant I12R/D34K/A132K with 8.1-fold, 8.6-fold, 6.6-fold, and 4.6-fold improved tolerance toward [BMIM]Cl, [BMIM]Br, [BMIM]I, and [BMIM][TfO], respectively, when compared to the wild-type BSLA. The obtained knowledge provides a lesson learned on forecasting enzyme stability in ILs and simplifies a rational design of the IL-tolerant enzymes.

Dr. Haiyang Cui was a PhD in Prof. Ulrich Schwaneberg Group in 2016-2020 and now as a postdoc in University of Illinois at Urbana-Champaign, USA (Prof. Huimin Zhao’ group). This work was realized in the division Computational Biology leaded by Dr. Mehdi D. Davari and was supported by computing resources granted by JARA-HPC from RWTH Aachen University (JARA0169 and JARA0187).

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Cui, H., Zhang, L., Yildiz, C.B., Eltoukhy, L., Cheng, L., Jaeger, K.E., Schwaneberg, U. and Davari, M.D., 2022. Enzyme Hydration: How to Retain Resistance in Ionic Liquids. ACS Sustainable Chemistry & Engineering. doi.org/10.1021/acssuschemeng.2c04216

  Universal correlation between ionic liquid resistance and hydration. Copyright: © ACS Sustainable Chemistry & Engineering Universal correlation between ionic liquid resistance and hydration and the practical substitution “ranking list” enable us to predict the enzyme stability in ILs and simplify the protocol to design the IL-tolerant enzymes rationally.