Structure and Function of Nifl1-2, A Novel Inhibitor of Nitrogenase Activity in th Earchaeon Methanococcus Maripaludis

University Of Washington, Seattle WA

Investigators

Abstract

Biological nitrogen fixation is a widespread metabolic process that converts atmospheric nitrogen into fertilizer through the biological activity of certain microorganisms. This project follows up on a newly discovered mechanism by which many organisms regulate the activity of nitrogenase, the enzyme that catalyses the biochemical reactions that result in nitrogen fixation. The mechanism involves a family of proteins called PII proteins that regulates nitrogen metabolic functions in a variety of organisms. The particular proteins to be studied in this research are the NifI proteins, which constitute a previously uncharacterized subfamily of PII proteins. Novel features of NifI and its regulation of nitrogenase activity include the formation a direct complex between NifI and the molybdenum-iron protein of nitrogenase, and formation of novel higher order structures of NifI complexed with itself. The research will involve biochemical, genetic, and protein structural studies using the model microbial species Methanococcus maripaludis, a member of the phylogenetic domain Archaea. The broader impacts of the research are environmental, agricultural, and educational. Biological nitrogen fixation contributes to the nutrition of microorganisms and the plants with which they associate, without the adverse environmental effects associated with chemical fertilizers. The work will also result in the training of personnel in the areas of microbiology and biochemistry, including the integration of protein structure with the biology of nitrogen fixation. Finally, the work feeds into the investigator's teaching and outreach efforts, which include courses featuring microbial metabolism, participation in the University of Washington's interdisciplinary graduate program in Astrobiology, and participation in a K-12 outreach program called project Astrobio.