Future directions in cofactor research: Discovery and development of coenzyme F420-dependent bioprocesses

• Applicant: Professor Dr. Gerald Lackner
• Subject Area: Microbial Ecology and Applied Microbiology ; Metabolism, Biochemistry and Genetics of Microorganisms
• Term: from 2018 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 408113938

Cofactors (coenzymes) are helper molecules that are crucial for the catalytic activity of many enzymes. While some cofactors are ubiquitous in nature, others are found in microbes with a highly-specialized metabolism. Coenzyme F420, for instance, plays a physiological role in methanogenic microbes, antibiotic-producing bacteria, as well as in the tuberculosis pathogen. F420-dependent enzymes are highly interesting for biocatalysis, since they are able to promote challenging chemical reactions. Despite these extraordinary features, F420 remains underexplored and barely used in biotechnology. One reason for this is the low availability of the cofactor as chemical synthesis is cumbersome and microbial sources of the cofactor are non-satisfactory at the moment. Therefore, our goal is to identify a missing step in the biosynthesis of F420 to produce it in the model bacterium Escherichia coli. Production titers will then be increased by rational genetic engineering as well as directed evolution. To effectively use cofactors, a regeneration system is required that resets the cofactor to its original state after reaction. Some do exist for F420, however, all of them suffer from severe limitations. Thus, we will establish an efficient regeneration system based on inexpensive substrates. These efforts will render F420 more attractive for biotechnological applications and will facilitate further work packages.In particular, we aim to identify novel F420-dependent bioprocesses with potential use for biotechnology. Our preliminary results corroborate recent bioinformatics studies that suggest that F420-dependent enzymes are more widespread than anticipated. Exploiting their ability to bind to F420, these enzymes will be enriched from various bacteria and tested for academically intriguing and biotechnologically useful activities. Additionally, we will investigate F420 in unusual ecological systems. To this end, we will address the symbiosis between bacteria and a mold fungus, the causative agent of rice seedling blight. Our preliminary results demonstrate that F420 is produced as soon as symbionts live in association with their fungal host. In collaboration, we want to elucidate the function of F420 in this model bacterial-fungal alliance that is of high importance for microbial ecology and plant pathology.

• DFG Programme: Research Grants