Ever since the 2003 publication of the initial 3DNA Nucleic
Acids Research paper (NAR03), the schematic diagrams of base-
pair parameters (see figure below) has become quite popular.
Over the years, we have received numerous requests for
permission to use the figure, or a portion thereof; as an
example, the figure has been adopted into a structural biology
textbook. In the 2008 3DNA Nature Protocols paper (NP08), we
devoted the very first protocol to “create a schematic image for
propeller of 45°”. Figure legend taken from Figure 1 of NAR03:
Pictorial definitions of rigid body parameters used to describe
the geometry of complementary (or non‐complementary) base pairs
and sequential base pair steps (19). The base pair reference
frame (lower left) is constructed such that the x‐axis points
away from the (shaded) minor groove edge of a base or base pair
and the y‐axis points toward the sequence strand (I). The
relative position and orientation of successive base pair planes
are described with respect to both a di