Intra-basepair Parameters Buckle(°) -90.63 Open angle(°) 57.96 Propeller (°) 54.68 Stagger (Å) -1.85 Shear (Å) 5.23 Stretch (Å) 2.92

Basepair Geometry C1'-C1' Distance(Å) 7.67 C6-C8 Distance (Å) 7.84 Opening (°) 127.64 Glycosidic angle- 1 (°) 38.60 Glycosidic angle- 2 (°) 92.85

Quantum Chemical interaction energy = -8.64 Kcal/mol

(Ref: Panigrahi et al.,Unpublished data)

Intra-basepair parameters and basepair geometry are calculated by NUPARM.