Structural studies of the effect that dimethyl sulfoxide (DMSO) has on cisplatin and carboplatin binding to histidine in a protein

The anticancer complexes cisplatin and carboplatin target the DNA major groove, but have toxic side effects. It is shown that in the presence of DMSO two molecules of either cisplatin or carboplatin bind to its His15 residue. The observation of this effect with DMSO, a widely used super-solvent for drug delivery, should be considered in toxicity assessments of these drugs.

Protonation-state determination in proteins using high-resolution X-ray crystallography: effects of resolution and completeness

A bond-distance analysis to determine the protonation states of ionizable amino acids has been made for trypsin at 1.2 Å resolution, subtilisin at 1.26 Å resolution and lysozyme at 0.65 Å resolution. This was effective for Asp and Glu but not for His.