Although RASMOL *claims* to use the DSSP algorithm for identifying Hbonds, it does not seem to use the entire algorithm as it reports many erroneous H-bonds that DSSP omits on geometric grounds. Rasmol seems to use only the distance and not the geometry of the hbond. ------------------------------------------------------------ Kevin Karplus karplus at soe.ucsc.edu http://www.soe.ucsc.edu/~karplus Professor of Biomolecular Engineering, University of California, Santa Cruz Undergraduate and Graduate Director, Bioinformatics (Senior member, IEEE) (Board of Directors, ISCB) life member (LAB, Adventure Cycling, American Youth Hostels) Effective Cycling Instructor #218-ck (lapsed) Affiliations for identification only.