Fig. 1

β-strand twisting and bending in Rheb. The small GTPase Rheb (Ras homolog enriched in brain) of the P-loop–containing nucleoside triphosphate hydrolase fold (PDB ID: 1XTQ). a Ribbon diagram showing the secondary and tertiary structures of Rheb. The individual β-strands of its twisted sheet are labeled A-E, and its α-helices are labeled A-D. b Each of the five β-strands is shown in two different orientations