The high-resolution crystal structure of an RNA/DNA dodecamer with the HIV-1 polypurine-tract sequence reveals an A-type hybrid duplex with a complete absence of any C2'-endo ribonucleotides and with segments of increased flexibility along the RNA chain.

Ultrahigh-resolution crystal structures of metal complexes of self-complementary Z-DNA with the sequence d(CG)₃ revealed different coordination patterns for Mn²⁺ (octahedral) and Zn²⁺ (octahedral and tetrahedral) cations. The complete sperminium cation is visible in electron density in the Mn²⁺ structure, while in the Zn²⁺ structure it is partly disordered in unison with fragments of the DNA molecule.