Predicted functional systems and metabolic pathways of the I. hospitalis-N. equitans system. The numbers refer to the corresponding genes in the I. hospitalis and N. equitans genome (green and red, respectively). Some of the biochemical pathways (carbon fixation, amino acid biosynthesis and sugar metabolism) have been experimentally validated [66,69]. Specific subcellular compartments and structures (periplasmic space, vesicles, tubules, pores, fibers) [9,11,62] are indicated and speculative functions are indicated with question marks. Scissors indicate proteases. Stars indicate specific regulatory proteins. Different transporter categories and their individual subunits are indicated by shape symbols and the direction of transport of specific substrates across the membrane is shown by arrows.
Podar et al. Genome Biology 2008 9:R158 doi:10.1186/gb-2008-9-11-r158