TY - JOUR
T1 - Structural Basis for Stabilization of Z-DNA by Cobalt Hexaammine and Magnesium Cations
AU - Gessner, Reinhard V.
AU - Quigley, Gary J.
AU - Wang, Andrew H.J.
AU - Rich, Alexander
AU - van der Marel, Gijs A.
AU - van Boom, Jacques H.
PY - 1985/1/1
Y1 - 1985/1/1
N2 - In the equilibrium between B-DNA and Z-DNA in poly(dC-dG), the [Co(NH3)6]3+ ion stabilizes the Z form 4 orders of magnitude more effectively than the Mg2+ ion. The structural basis of this difference is revealed in Z-DNA crystal structures of d(CpGpCpGpCpG) stabilized by either Na+/Mg2+ or Na+/Mg2+ plus [Co(NH3)6]3+. The crystals diffract X-rays to high resolution, and the structures were refined at 1.25 A. The [Co(NH3)6]3+ ion forms five hydrogen bonds onto the surface of Z-DNA, bonding to a guanine O6 and N7 as well as to a phosphate group in the Zn conformation. The Mg2+ ion binds through its hydration shell with up to three hydrogen bonds to guanine N7 and O6. Higher charge, specific fitting of more hydrogen bonds, and a more stable complex all contribute to the great effectiveness of [Co(NH3)6]3+ in stabilizing Z-DNA.
AB - In the equilibrium between B-DNA and Z-DNA in poly(dC-dG), the [Co(NH3)6]3+ ion stabilizes the Z form 4 orders of magnitude more effectively than the Mg2+ ion. The structural basis of this difference is revealed in Z-DNA crystal structures of d(CpGpCpGpCpG) stabilized by either Na+/Mg2+ or Na+/Mg2+ plus [Co(NH3)6]3+. The crystals diffract X-rays to high resolution, and the structures were refined at 1.25 A. The [Co(NH3)6]3+ ion forms five hydrogen bonds onto the surface of Z-DNA, bonding to a guanine O6 and N7 as well as to a phosphate group in the Zn conformation. The Mg2+ ion binds through its hydration shell with up to three hydrogen bonds to guanine N7 and O6. Higher charge, specific fitting of more hydrogen bonds, and a more stable complex all contribute to the great effectiveness of [Co(NH3)6]3+ in stabilizing Z-DNA.
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U2 - 10.1021/bi00323a001
DO - 10.1021/bi00323a001
M3 - Article
C2 - 3978072
AN - SCOPUS:0022425387
SN - 0006-2960
VL - 24
SP - 237
EP - 240
JO - Biochemistry
JF - Biochemistry
IS - 2
ER -