Fig. 1.

A The main structural regions in depicted on 3D structure of G domain of K-Ras-GTP (based on PDB structure: 6MNX, chain B). The picture was produced by using The PyMOL Molecular Graphics System, version 2.0 Schrödinger, LLC. software. α1–α5 helices, β1–β6 sheets as well as P-loop, switch I and switch II are indicated. N-terminus and C-terminus are shown as Nt and Ct, respectively, Mg²⁺ is depicted as a gray sphere. B Sequence alignment of the four most relevant Ras proteins: K-Ras4A, K-Ras4B, H-Ras, and N-Ras. Residues that are distinct among their sequence are underlined. Secondary structural elements, as well as the P-loop, switch I, and switch II regions are indicated above the sequence colored as in A. G domain (effector and allosteric lobes) and hypervariable region (HVR) are shown as well. Farnesylated and palmitoylated cysteines are shown with yellow and cyan background in the sequence, respectively