Figure 5.

Peptide ligands do not affect individual Hop TPR domain structures. Individual TPR domains were incubated overnight with or without a 100-fold molar excess of peptide corresponding to Hsp70 or Hsp90, and CD spectra were obtained. (A) TPR1 was incubated in the absence or the presence of the Hsp70-related peptide PTIEEVD, which is known to bind specifically to TPR1. The MRE values for TPR1 with PTIEEVD were divided by 2 to correct for instrument differences. (B) TPR2a was incubated in the absence or the presence of the Hsp90-related peptide SRMEEVD, which is known to bind specifically to TPR2a. (C) Since a ligand for TPR2b is unknown, this domain was incubated with either Hsp70 or Hsp90 peptide. In no instance did peptide alter the secondary structure of TPR domains.