(A) Differences in HDX are represented by relative deuterium levels of inactive protein covalently bound to compound minus that of inactive GDP-bound protein alone, scale shown at top. Two-dimensional representations of KRAS G12C are given in linear fashion from N terminus (top) to C terminus (bottom), and the locations of key structural elements are shown on the left. All deuterium-labeling time points are shown, increasing from left to right.
(B and C) Crystal structures of 1 (B) or ARS-853 (C) bound to KRAS G12C with HDX MS differences at labeling time point 1 min (upper panel) and 4 hr (lower panel) annotated using the color scheme from subpanel (A).
(D) KRAS G12C bound to GDP alone (PDB: 4LDJ) provided for comparison. In (D), switch I is shown in yellow and switch II in green; magnesium is represented as a magenta sphere.