fig2

Figure 2. Crystal structure of K-RAS 4B GDP in ribbon representation (4EPY). The α-helices (α1-α5), β-sheets (β1-β6), the magnesium-ion (Mg2+), and the GDP nucleotide are labeled in black. The loops and switch regions are color-coded as follows: P-loop (red); switch I - SW-I (green); G3-loop (blue); switch II - SW-II (yellow); G4-loop (magenta); G5-loop (orange)