Figure 2.

Comparison of Saccharomyces cerevisiae Vps21 to Homo sapiens RHEB.

Crystal structure (1.48 Å resolution) of yeast Vps21 (green) bound to the non-hydrolyzable GTP analog GppNHp (PDB: 1EK0) [83] was aligned with the crystal structure (2.65 Å resolution) of GppNHp-bound RHEB (fuschia) (PDB: 1XTR) [84] by superimposing the GTP-binding fold in each of these two GTPase, revealing the distinct conformation of the Switch II regions (top) in these proteins. Side chains in the Switch I and Switch II loops in both GTPases are shown in stick representation.