a Wildtype ClC-ec1 (homodimer, 100 kDa), methionine methyl region.
b Monomeric ClC-ec1 (I201W/I422W, 50 kDa).
c [H+]-dependence of 1H-13C HSQC spectra: blue, pH 7.5; orange, pH 5.0; black, reversal to pH 7.5. The asterisk (*) and dagger (†) indicate the most clearly resolved crosspeaks that exhibit H+-dependency.
d Partially deuterated (∼80%) monomeric ClCe-c1 with prolonged data collection. e Size exclusion chromatograms of ClC-ec1. Top WT ClC-ec1; Middle monomeric ClC-ec1 (mClC-ec1) (I201W/I422W); Bottom Δ6 mClC-ec1 (mutating six Met residues as follows: M38L, M65I, M228V, M276T, M330V, and M332L) yields a mix of dimer and monomer populations.