Biochemistry and Molecular Genetics of Formate Utilization in Methanogenic Archaebacteria

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The enzyme requirements for growth on formate, and expression of the formate dehydrogenase operon in Methanobacterium formicicum, will be studied. The specific aim is to identify the factors require for efficient initiation of transcription of the highly expressed formate dehydrogenase operon using an in vitro cell-free transcription system. The results are expected to extend the current view of methanogenesis beyond a biochemical understanding, and reveal new principles of gene expression in the archaebacteria. The long-term goal is to utilize in vivo molecular approaches (i.e. site-directed mutagenesis) to study (i) fundamental principles of transcription in the archaebacteria, and (ii) the biochemical mechanism of formate dehydrogenase (and other enzymes) required for formate utilization. The research proposed here, together with work in progress to develop a transformation system, will lay the foundation for these long-term goals. %%% The process of biological methanogenesis occurs in a variety of anaerobic habitats and is a significant component of the global carbon cycle. Methanogenic organisms are archaebacteria which are phylogenetically distinct from eubacteria and eukaryotes; thus, the study of these unusual organisms offer a third perspective to study fundamental cellular processes. The present understanding of methogenesis is largely based on microbiological and biochemical studies. This research will combines molecular genetic and biochemical approaches to investigate the pathway of formate-dependent CO2 reduction to methane.