Figure 2

The translational protein G-domain secondary structure topologies. 2a displays the G-domain topologies for the bacterial proteins plus Ras and SRP54. 2b displays those for the archaeal translational proteins. These are based on the same PDB data represented in Figure 1, with the addition of 5P21 for Ras and 1J8M for SRP54. The topology of SR-alpha, and the bacterial Ffh and FtsY are not shown as they are nearly identical to that of SRP54. The triangles represent beta strands; the circles represent alpha helices. The region of the P-loop motif adjoining strand and helix are colored purple for reference. The highly variable switch region beta strands are colored blue. The yellow represents the large insertions in EF2/EFG relative to Ras. The white circles represent the significant length reduced helices in the bacterial IF2 and the archaeal aeIF2 gamma.