Fig. 1.

KRAS₁₆₉^Q61H structure analysis using new crystallization conditions. KRAS₁₆₉^Q61H protein was crystallized with bound GTP-analog GppNHp. (A) Surface representation of the asymmetric unit containing the six KRAS₁₆₉^Q61H proteins in different colors with different chains, labeled A–F. (B) Ribbon representation of KRAS₁₆₉^Q61H showing an overlay of the six chains, of the asymmetric unit. The switch regions of five proteins (B–F) are identical (depicted in dark gray), and one (chain A) has a stabilized switch I and switch II (depicted in blue) due to interactions with neighboring protein molecules in the crystal lattice. Residue H61 and GppNHp are indicated and one Mg atom (shown as a magenta sphere) was identified per chain. C and D show ribbon representation overlays of the KRAS₁₆₉^Q61H (chain A) structure with KRAS₁₈₈^G12V (C, switch I and switch II depicted in green) and KRAS₁₈₈^G12D (D, switch I and switch II depicted in brown), highlighting structural conservation across RAS mutations.