High-resolution crystal structure of Z-DNA in complex with Cr(3+) cations.

ABSTRACT: This work is part of our project aimed at characterizing metal-binding properties of left-handed Z-DNA helices. The three Cr(3+) cations found in the asymmetric unit of the d(CGCGCG)2-Cr(3+) crystal structure do not form direct coordination bonds with atoms of the Z-DNA molecule. Instead, the hydrated Cr(3+) ions are engaged in outer-sphere interactions with phosphate groups and O6 and N7 guanine atoms of the DNA. The Cr(3+)(1) and Cr(3+)(2) ions have disordered coordination spheres occupied by six water molecules each. These partial-occupancy chromium cations are 2.354(15) Å apart and are bridged by three water molecules from their hydration spheres. The Cr(3+)(3) cation has distorted square pyramidal geometry. In addition to the high degree of disorder of the DNA backbone, alternate conf

SUBMITTER: Drozdzal P 

PROVIDER: S-EPMC4381091 | biostudies-literature | 2015 Apr

REPOSITORIES: biostudies-literature