Figure 2.

(A) Disorder at the Lys34-sclx₈ site increases with increasing pH in the P2₁3 form. In contrast, Arg34 is fully defined in the RSL-R₆ variant. (B) Electron density in the RSL-sclx₈ crystal structure at pH 8.5 is consistent with alternate conformations for one calixarene monomer, highlighted with a dashed box. Alternate conformers 1 and 2 of sclx₈ were modeled at 55 and 45% occupancy, respectively. 2Fo-Fc electron density maps (contoured at 1.0 σ) are shown as green mesh.