Figure 4. Crosslink- and mass spectrometric analysis of the Hsp90 PPH-5 interaction.

MS/MS-spectra of the identified light and the corresponding heavy intermolecular cross-link peptide (A) Shown is a schematic representation of the results of three crosslinking experiments. Analysis revealed a potential contact site between the phosphatase domain of PPH-5 (red) and the middle/C-terminal interface of CeHsp90 (blue) as indicated by the lines connecting the two proteins. (B) CeHsp90-K510 – PPH-5-K205 and cross-link peptide (C) CeHsp90-K551 – PPH-5-K205, common b- and y-ions are marked with green stars. Cross-linker containing fragment-ions (red stars) of the light crosslinked peptide (light-CL peptide) and the heavy crosslinked peptide (heavy-CL peptide) are illustrated in the MS/MS-spectra by red stars and show a mass shift of 6.0437/z.