Fig. 2: Structure of GDP-bound wild-type KRAS.

A Surface representation of the KRAS protein, highlighting frequently mutated residues. Residues Q61 (red), G12 and G13 (orange), K117 (yellow), and A146 (blue) are labeled and color-coded. The bound GDP molecule is shown in ball-and-stick representation. B Close-up view of the GDP binding site in wild-type KRAS. The GDP molecule is subdivided into diphosphate, ribose, and guanine moieties. Atoms are color-coded (carbon in gray, oxygen in red, nitrogen in blue, and phosphorus in orange). Key interactions between KRAS residues (G12, G13, K117, and A146) and GDP are shown as dashed lines: hydrogen bonds (blue), ionic interactions (yellow), and weak hydrogen bonds (gray). The distance between the oxygen of G12 and the nitrogen of K117, forming a hydrogen bond, is 2.94 Å. Structure from reference66 (ID: 5W22).