Hi everyone,

I took a PDB structure and I wish to characterize the pKa value of histidine. However, I don't know how configure the "Protonate Protein/At pH" menu.

My structure is on pH 7.3, so I set the pH between 7.2 and 7.4. What value I use to set up the "Protonate Protein/At pH" menu (the standard value is 7.4).