Fig. 9.

Waters involved in intra-octamer and inter-octamer contacts. (a) The octamer formed from the ASU strands of structure P1A is shown in yellow thick lines and adjacent octamers linked by water contacts are shown in blue thin lines. Waters whose potential contacts are limited to a single octamer are colored magenta; waters that form possible cross-octamer contacts are colored teal. (b) A network of hydrogen bonds involving two waters and four O2′ residues stabilizes cross-strand linkage in structure P1B.