Enzyme-polyelectrolyte complexes boost the catalytic performance of enzymes
Martin J. Thiele, Mehdi D. Davari, Melanie König, Isabell Hofmann, Niklas O. Junker, Tayebeh Mirzaei Garakani, Ljubica Vojcic, Jörg Fitter, Ulrich Schwaneberg, ACS Catalysis, 2018, DOI: 10.1021/acscatal.8b02935
In the present publication, a molecular understanding was reported on polyelectrolyte-enzyme complexes which boost enzymatic activity in multi-component systems.
In this publication, a molecular understanding of the boosting effect of polyacrylic acid -PAA-) and poly-L-γ-glutamic acid -γ-PGA- for a nonspecific subtilisin protease was generated through biophysical characterization, e.g. fluorescence correlation and circular dichroism spectroscopies, isothermal titration calorimetry, molecular dynamics simulations and protease reengineering, e.g. site-saturation mutagenesis. This study revealed that enthalpically driven interactions via key amino acid residues close to the protease Ca2+ binding sites cause the boosting effect in protease activity. On the molecular level electrostatic interactions result in the formation of protease-polyelectrolyte complexes. Site-saturation mutagenesis on 6 positions yielded an increased proteolytic performance against a complex protein mixture -trademark CO3; up to ~300% and ~70%- in the presence of PAA and γ-PGA. Being able to fine-tune interactions between proteins and negatively charged polymers through integrative use of computational design, protein reengineering and biophysical characterization proved to be an efficient workflow to improve protease performance.
This research was partially funded by Henkel AG & Co. KGaA, Düsseldorf, Germany, as part of the Henkel Innovation Campus for Advanced Sustainable Technologies -HICAST- project. Simulations were performed with computing resources granted by JARA-HPC from RWTH Aachen University under projects RWTH0116 and JARA0169.