Figure 6.

Functional effects of the substitution of native residues by cysteines and their endogenous disulfide crosslinking. Eight pairs of Cys-substituted α and Cys-substituted β4 were expressed in HEK 293 cells. Recordings were in outside-out macropatches with 10 μm Ca²⁺ in the pipette. Black bars show the effects attributable to the disulfide, and gray bars show the effects attributable to the substitution of the two Cys for native residues. Effects on V₅₀ (A), the rate constant for opening (B), and the rate constant for closing (C) were extrapolated to 100% crosslinking or 100% reduction as described previously (Liu et al., 2008b). SS, Disulfide-bonded Cys; SH, reduced Cys.