Movement of S6 during gating. Bulk motions of S6 appear to differ between Slo1 and Kv1.2, but changes in accessibility or orientation of aSlo1 S6 residues between liganded and metal-free structures are minimal. (A) Schematic showing counterclockwise movement of vector between diagonal Cα position of P309 residues between ligand-free (red) and liganded (blue) structures. ΔAngle corresponds to measured angle. (B) Plot of angular rotation determined as in A for aSlo1 (red) and Kv1.2 (black). (C) Comparison of absolute distance of Cα carbon from pore axis at each amino residue along S6 for liganded and metal-free Slo1 structures. Larger red circles correspond to residues readily modified by MTSET when substituted with Cys (mA313, mA316, mS317, mE321). (D) Similar comparison as in C, but for Kv1.2. Green line corresponds to metal-free Slo1 highlighting similarity in positioning of homologous residues between Kv1.2 and aSlo1 S6. (E) Change in Cα position relative to pore axis between more likely closed and open conformations for aSlo1 and Kv1.2. (F) Assessment of aqueous solvent accessibility for liganded and metal-free aSlo1 structures.