https://www.ncbi.nlm.nih.gov/Structure/pdb/4XQZ
4XQZ: Calcium(II) and copper(II) bound to the Z-DNA form of d(CGCGCG), complexed by chloride and MES
DNA (5'-D(*CP*GP*CP*GP*CP*G)-3')2-(N-MORPHOLINO)-ETHANESULFONIC ACIDCALCIUM IONCHLORIDE IONCOPPER (II) ION