Simultaneous N7,O6-Binding of Guanine to Two Zinc Centers and Its Possible Biological Significance

The reaction of ZnCl2 with 9-ethylguanine (9-EtGH) produced a
novel dinuclear Zn(II) complex, [Zn2Cl4(H2O)(μ-9-EtGH-N7,O6)(9-EtGH-N7), 1. The X-ray structure analysis (monoclinic, P21 (No.
4), a = 11.0636(6) Å, b = 6.6546(4) Å, c = 15.9630(9) Å, β =
101.069(1)°, V = 1153.4(1) Å3, Z = 2) revealed that one of the
tetrahedrally coordinated Zn(II) atoms binds to the N7 site of
9-EtGH and to the exocyclic O6 atom of another 9-EtGH molecule.
The remaining Zn(II) atom binds to the N7 site of the second
9-EtGH moiety.