Table 1.

The 108 observed and potential geometric base triple families, grouped in 18 triple superfamilies

Each triple family is assigned a unique number between 1 and 108, but has two names, depending on which component base pair is given first, and thus belongs to two superfamilies. For example, triple family #1 is cWW/cHW or cWH/cWW, depending how the bases are ordered, and belongs to both the cWW and cHW superfamilies (first two columns). For each entry, the chain orientations, parallel (P) or anti-parallel (A), between the 1st and 2nd, 2nd and 3rd and 1st and 3rd nucleotides of the triple are also given, assuming all the nucleobases are in the default anti glycosidic bond configuration. The second appearance of each family in the table is indicated using italic font. Triple families for which instances have not yet been observed in the structure database appear with a gray background.