Hi, for the structure 2chj,

http://www.rcsb.org/pdb/explore/explore.do?structureId=2chj, DSSR produces some odd output.

First, it identifies two helices instead of one. This is somewhat understandable since removing two strands would still produce a helical structure, but it would be nice if DSSR could identify higher-order helices automatically. Perhaps the definition of a base-pair could be generalized to include any number of nucleotides, and helices could be defined based on the stacking of these generalized base-pairs.

Second, it identifies each strand as a single-stranded segment, which is clearly a bug. Not sure how a single-stranded segment is defined, but I'm guessing it has to do with there being no first order base pairs (i.e. one to one base pair) in the structure.