TY - JOUR
T1 - The interactions of ruthenium hexaammine with z-dna:Crystal structure of a ru(nh3˜3 salt of d(cgcgcg) at 1.2 a resolution
AU - Ho, Pui S.
AU - Frederick, Christin A.
AU - Saal, Daniel
AU - Wang, Andrew H.J.
AU - Rich, Alexander
N1 - Funding Information:
We acknowledge Gijs A van der Marel and Jacques H. van Boom for assistance in the preparation of the oligonucleotides. This research was supported by grants from the National Institutes of Health, the American Cancer Society, the National Aeronautics and Space Administration, the Office of Naval Research, and the National Science Foundation. P.S.H. is a fellow of the American Cancer Society and C.AF. is a fellow of the Leukemia Society.
PY - 1987/2
Y1 - 1987/2
N2 - A crystal of d(CGCGCG) in the Z-DNA lattice was soaked with ruthenium(III) hexaammine and its structure refined at 1.2 A resolution. Three unique metal complexes were found adsorbed to each hexamer duplex. In addition, two symmetry-related binding sites were located, yielding a total of five ruthenium complexes bound to each d(CGCGCG) duplex. One unique site and its symmetry related site are nearly identical to the binding site of cobalt(III) hexaammine on Z-DNA At that position, the metal complex bridges the convex surfaces of two adjacent Z-DNA strands by hydrogen bonds to the N7 and 06 functional groups of the guanine bases. The remaining three ruthenium(III) hexaammine binding sites are not present in the cobalt(III) hexaammine Z-DNA structure. Of these, two are related by symmetry and span the gap between the convex outer surface of one Z-DNA strand and the helical groove crevice of a neighboring strand. The third ruthenium site has no symmetry mate and involves interactions with only the deep groove. In this interaction, the metal complex hydrogen bonds to both the phosphate backbone and to a set of primary shell water molecules that extend the hydrogen bonding potential of the deep groove crevice out to the surface of the molecule. Solution studies comparing the circular dichroism spectra of lowsalt poly(dG-dC) · poly(dG-dC) samples in the presence ofruthenium(III) and cobalt(III) hexa-ammine show that the ruthenium complex does stabilize Z-DNA in solution, but not as effectively as the cobalt analogue. This suggests that some of the interactions available for the larger ruthenium complex may not be important for stabilization of the left-handed DNA conformation.
AB - A crystal of d(CGCGCG) in the Z-DNA lattice was soaked with ruthenium(III) hexaammine and its structure refined at 1.2 A resolution. Three unique metal complexes were found adsorbed to each hexamer duplex. In addition, two symmetry-related binding sites were located, yielding a total of five ruthenium complexes bound to each d(CGCGCG) duplex. One unique site and its symmetry related site are nearly identical to the binding site of cobalt(III) hexaammine on Z-DNA At that position, the metal complex bridges the convex surfaces of two adjacent Z-DNA strands by hydrogen bonds to the N7 and 06 functional groups of the guanine bases. The remaining three ruthenium(III) hexaammine binding sites are not present in the cobalt(III) hexaammine Z-DNA structure. Of these, two are related by symmetry and span the gap between the convex outer surface of one Z-DNA strand and the helical groove crevice of a neighboring strand. The third ruthenium site has no symmetry mate and involves interactions with only the deep groove. In this interaction, the metal complex hydrogen bonds to both the phosphate backbone and to a set of primary shell water molecules that extend the hydrogen bonding potential of the deep groove crevice out to the surface of the molecule. Solution studies comparing the circular dichroism spectra of lowsalt poly(dG-dC) · poly(dG-dC) samples in the presence ofruthenium(III) and cobalt(III) hexa-ammine show that the ruthenium complex does stabilize Z-DNA in solution, but not as effectively as the cobalt analogue. This suggests that some of the interactions available for the larger ruthenium complex may not be important for stabilization of the left-handed DNA conformation.
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U2 - 10.1080/07391102.1987.10507657
DO - 10.1080/07391102.1987.10507657
M3 - Article
C2 - 3271453
AN - SCOPUS:0023115168
SN - 0739-1102
VL - 4
SP - 521
EP - 534
JO - Journal of Biomolecular Structure and Dynamics
JF - Journal of Biomolecular Structure and Dynamics
IS - 4
ER -