The crystal structure of Z-DNA with untypically coordinated Ca²⁺ ions.

ABSTRACT: DNA oligomer duplexes with alternating cytosines and guanines in their sequence tend to form helices of the Z-DNA type, where the sugar and phosphate backbone forms a left-handed helix in a zigzag fashion with a repeat of two successive Watson-Crick pairs of nucleotides. Z-DNA duplexes often crystallize in complexes with diverse metal ions interacting with polar DNA atoms in various ways. This work describes the high-resolution crystal structure of a Z-DNA d(CGCGCG)₂ duplex in complex with Ca²⁺ ions, unusually coordinated as an approximate pentagonal bipyramid by two neighboring guanines through their O6 and N7 atoms and a water molecule in the equatorial plane and a phosphate oxygen atom and another water molecule in the apical positions.

SUBMITTER: Luo Z 

PROVIDER: S-EPMC7983155 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature