Thanks for using 3DNA!
The input file you attached can in principle be generated using any text editor (e.g., vi or emacs, if you are Unix orientated). However, it is more conveniently created by 3DNA itself after analyzing a structure. The point is best illustrated with an example. Download
1bna (the classic Dickerson B-DNA dodecamer) in PDB format (1bna.pdb), and do the followings:
find_pair 1bna.pdb 1bna.bps
analyze 1bna.bps
In addition to the main output file
1bna.out, you will also see a few other files including
bp_step.par which is in the exact format as illustrated in your attachment.
An updated user manual for 3DNA v2.x is in progress. In the meantime, please try to reproduce all the recipes of the 2008
Nature Protocols paper to get a better understanding of what 3DNA has to offer. Remember any related questions are welcome on the Forum.
Best regards,
Xiang-Jun