Figure 1.
Prominent first-shell hydration patterns around [d(CGCGCG)]2 (PDB ID 1ICK (47)). (A) Standard C:G base pair. Longitudinal patterns bridging base atoms from opposite strands include (B) a water spine inside the minor groove that links cytosine O2 atoms, (C) waters between guanine O6 atoms on the convex surface and (D) water tandems that link cytosine N4 atoms on the convex surface. (E) Water molecules at the periphery of the minor groove linking guanine N2 atoms to 5′- and 3′-adjacent phosphate groups in a transverse fashion. Fourier 2Fo-Fc sum electron density drawn at the 1σ level surrounds water molecules and individual nucleotides. Water molecules are cyan spheres, atoms engaged in H-bonds are highlighted as spheres and H-bonds are drawn with thin solid lines.