Fig. 5

Steady-state tryptophan fluorescence of \({\mathbf{C}}_{{\mathbf{4}}}^{{\mathbf{P}}} - {\mathbf{D}}^{{{\mathbf{WW}}}}\) upon titration with \({\mathbf{C}}_{{\mathbf{4}}}^{{\mathbf{P}}} - {\mathbf{D}}^{{{\mathbf{PPxY}}}}\) (a) and \({\mathbf{C}}_{{\mathbf{4}}}^{{\mathbf{P}}} - {\mathbf{D}}^{{{\mathbf{PPxY}} ^* }}\) (b). The top graphs present tryptophan fluorescence spectra obtained for \({\mathbf{C}}_{{\mathbf{4}}}^{{\mathbf{P}}} - {\mathbf{D}}^{{{\mathbf{WW}}}}\) upon addition of different concentrations of \({\mathbf{C}}_{{\mathbf{4}}}^{{\mathbf{P}}} - {\mathbf{D}}^{{{\mathbf{PPxY}}}}\) and \({\mathbf{C}}_{{\mathbf{4}}}^{{\mathbf{P}}} - {\mathbf{D}}^{{{\mathbf{PPxY}} ^* }}\). The bottom graphs show titration of \({\mathbf{C}}_{{\mathbf{4}}}^{{\mathbf{P}}} - {\mathbf{D}}^{{{\mathbf{WW}}}}\) with \({\mathbf{C}}_{{\mathbf{4}}}^{{\mathbf{P}}} - {\mathbf{D}}^{{{\mathbf{PPxY}}}}\) and \({\mathbf{C}}_{{\mathbf{4}}}^{{\mathbf{P}}} - {\mathbf{D}}^{{{\mathbf{PPxY}} ^* }}\), where fluorescence was monitored at 340 nm. Error bars represent s.d. (n = 3)