Neutral Cellobiose Dehydrogenases and Laccaes of Meso- and Thermophilic Ascomyctes: gene structure, mechanism, and applications in nanoelectronics

It is the objective of the project to compare the properties of neutral CDHs from meso- and thermophilic ascomycetes with respect to their basic kinetic and biochemical properties, their primary structures, and their reaction mechanisms. Such a detailed study on ascomycete CDH has not been performed previously. It will help us to understand the basic reaction mechanisms of members of CDH class-2, including the transport of the electrons between the substrates and the two redox centres of the flavocytochrome. In addition, it is planned to clone both neutral CDH and laccase from selected ascomycetes (e.g., from the two Chaetomium species of the Russian partner) and to express these enzymes in suitable host organisms. Ascomycetes are, in general, more amendable to genetic manipulation than basidiomycetes, and elucidation of the biological function of CDH by molecular biological approaches seems more promising than in basidiomycetes. Therefore, detailed investigations of CDH and laccase enzymes and their encoding genes are planned at BOKU. Information obtained in the course of the proposed cooperation will be a tremendously valuable contribution. A more detailed knowledge on the mechanistic and kinetic properties and the increased availablity of these biocatalysts through overexpression will be the basis for a wider biotechnological application of these enzymes, e.g., in nanobiotechnology and nanoelectronics such as the construction of new biosensors with improved properties.