G protein/Ras-RasGAP complex, mol. model

Molecular model of the active site of Ras with GDP and ALF3 shown as stick models andp rotein side- chains as ball-and-stick models. The RasGAP residues are labelled in italic. Hydrogen bonds formed by R789 of GAP are dashed lines. ALF3 is used in structural studies as an analogue of the gamma-phosphate of ATP. Ras proteins are the smallest G proteins comprising the common core of the G protein fold, binding GDP/GTP and having intrinsic GTPase activity. GTPase activating protein (GAP) stimulates GTPase of normal but not oncogenic RAS P21. PDB code 1wq1.