Phylometabolic reconstruction of the carbon fixation pathway within the aquificae

Phylometabolic analysis (Braakman and Smith, 2012) was used to investigate the carbon fixation pathway in T. ammonificans and its evolutionary relationship to the carbon fixation pathways present in other members of the Aquificae phylum. In phylometabolic analyses, the metabolic pathways of the organism under investigation are compared to those found in related organisms both within and across neighboring clades. By focusing on the pathways, the comparison may reveal variations in multi-enzyme functional units, providing context for the completion of the pathway within the networks of individual organism, while also allowing for the identification of ancestral states and horizontal gene transfer events. The resulting phylometabolic tree includes multiple complete pathways to common essential metabolites, and suggests which evolutionary substitutions are allowed (at either organism or ecosystem levels) among these pathways (see [Braakman and Smith, 2012] and reference therein for a more extensive description of the principles underlying this approach). We reconstructed the carbon fixation pathways in representative genomes of the Aquificae, and compared them. Information regarding the carbon fixation metabolic network was implemented using phylogenetic and comparative genomic information to help reconstruct possible ancestral states of the carbon fixation network based on maximum parsimony principles.