Figure 5.

PPIase activity of TF and TF mutants. A, evaluation of PPIase activity of TF and TF variants by refolding assay of RCM-RNase T1. Refolding of RCM-RNase T1 in the absence and presence of TF or TF mutants was monitored by increase of intrinsic tryptophan fluorescence at 320 nm after excitation at 268 nm. The experiments were performed at 15 °C. Because of the complex process of the refolding of RCM-RNase T1 (37), refolding rates were not extracted. B, evaluation of PPIase activity of TF and TF variants by NMR relaxation dispersion experiments. The chemical exchange in MBP Gly²⁵⁴ coupled with cis/trans isomerization of peptidyl–prolyl bond between MBP Gly²⁵⁴ and Pro²⁵⁵ in complex with TF^PPD (left panel) or TF^{PPD, I195P} (right panel) was monitored.