Right-handed Z-DNA at ultrahigh resolution: a tale of two hands and the power of the crystallographic method.

ABSTRACT: The self-complementary L-d(CGCGCG)₂ purine/pyrimidine hexanucleotide was crystallized in complex with the polyamine cadaverine and potassium cations. Since the oligonucleotide contained the enantiomeric 2'-deoxy-L-ribose, the Z-DNA duplex is right-handed, as confirmed by the ultrahigh-resolution crystal structure determined at 0.69 Å resolution. Although the X-ray diffraction data were collected at a very short wavelength (0.7085 Å), where the anomalous signal of the P and K atoms is very weak, the signal was sufficiently outstanding to clearly indicate the wrong hand when the structure was mistakenly solved assuming the presence of 2'-deoxy-D-ribose. The electron density clearly shows the entire cadaverinium dication, which has an occupancy of 0.53 and interacts with one Z-DNA

SUBMITTER: Drozdzal P 

PROVIDER: S-EPMC9912920 | biostudies-literature | 2023 Feb

REPOSITORIES: biostudies-literature