Transmembrane topology analysis. The graphs show the distribution of proteins with different membrane topologies for the membrane proteome. Proteins with the N-terminal located on the outside of the membrane are plotted upwards and those with the N-terminal on the inside are plotted downwards. The colors of the bars represent the proportion of different functional groups and unclassified proteins for a topology. The topologies have been predicted for each protein with Phobius. A. The graph shows the distributions of proteins predicted to have one TM helix. B. The graph shows the distribution of proteins predicted to have multiple TM helices. Forty-three proteins with more than 14 TM helices have been excluded from graph B.