4R15: High-resolution Crystal Structure Of Z-dna In Complex With Cr3+ Cations

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) A 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 conformations are also observed for the deoxyribose and base moieties of the G2 nucleotide. Our work illuminates the question of conformational flexibility of Z-DNA and its interaction mode with transition-metal cations.
PDB ID: 4R15Download
MMDB ID: 127459
PDB Deposition Date: 2014/8/4
Updated in MMDB: 2015/04
Experimental Method:
x-ray diffraction
Resolution: 0.97  Å
Biological Unit for 4R15: dimeric; determined by author and by software (PISA)
Molecular Components in 4R15
Label Count Molecule
Nucleotide(1 molecule)
DNA (5'-d(*cp*gp*cp*gp*cp*g)-3')
Molecule annotation
Chemicals (3 molecules)
* Click molecule labels to explore molecular sequence information.

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