
Observed geometries of 7G-A (left: A,B) and 7G-G (right: C,D) for the 5′G7GC/3′CXG (up: A,C) and 5′C7GG/3′GXC (down: B,D) contexts (X indicates A or G). The proposed geometries for the 7G-A and 7G-G pairs corresponding to the different contexts are shown within blue rectangles.










