A cellular hydrogen sensor for enzyme engineering

Biocatalysis has emerged as a widely-used catalytic method for the manufacture synthesis of a wide range of chemical and pharmaceutical products under mild conditions. Due to its outstanding sustainability, biocatalysis has the potential to make a strong contribution to a development towards a zero-carbon society. As enzymes are usually not optimized for the requirements of a biotechnological processes, protein engineering directed enzyme evolution is often used to adapt their catalytic properties. While these methods have been very successful for the development of improved enzyme variants, the learning potential remains usually very limited as only a handful of improved variants is isolated. In contrast, deep mutational scanning allows to correlate systematically the effect of a large number of mutants with a given catalytic property. H2aseScanning aims to use the energy module of autotrophic microorganisms for the coupling of enzyme activity with cell growth, which then allows to analyze the enrichment of enzyme variants with higher activity. The resulting Fitness Landscapes are expected to increase the understanding of structure-function relationships of enzymes that are vital for metabolism of CO2-fixing organisms. 1