FIGURE 6.

Time courses for the alkylation reactions of cysteine residues in the L18 shows accessibility of WT (A) and mutant (B and C) LHC proteins. A–C, Lhcb5 L170C (A), ΔTM2 G158C (B), and ΔTM3 G158C (C) were labeled with 30-fold excess N-ethyl-maleimide in denaturant guanidinium hydrochloride (GdmHCl), pH 7.5 (black traces) and in aqueous buffer, pH 7.5 (red traces), and the reactions were quenched at different time points with DTT and subjected to intact protein mass spectrometry as in the accompanying manuscript (34).