Fig 1. Assessment of nucleotide-binding site of K-Ras bound to GTP/GDP.

(A) Cartoon representation of K-Ras structure bound to GNP (PDB ID: 2PMX). The β-strands, α-helices, and coils are shown in orange, blue, and gray colors, respectively. The P-loop, switch I, and switch II domains are indicated in red, blue, and green boxes, respectively. (B) Surface representation of GTP-bound K-Ras along with its nucleotide-binding sites. (C) Arrangements of the 7-residue binding interface in the GTP-bound K-Ras. (D) Calculation of H-bond distances between the atoms of 12 common nucleotide-binding residues and GTP/GDP in all studied K-Ras mutants. The H-bond length of 7 residues located outside of the previously characterized GTP/GDP-binding site is shown in red boxes. (E) Effects of the oncogenic mutations on switch I (blue) and (F) switch II (green) domains of K-Ras mutants.