Hi,

This is our peptide proton NMR with water suppression. The solvent we are using is 90% 20mM phosphate buffer + 10% D2O (pH=7). The problem we had is that the NMR of this peptide has the mess peaks between 6ppm and 5ppm. Our peptide is very pure after HPLC purification. We tried commercial buffers and our own prepared buffer, and both had this problem. We also made sure that the D2O did not contain any impurities.

The peptide we are used is three strand Pin WW domain peptide. Could you give us some advice about what these mess peaks are?

Thank you for your help!

Haoliang