Dear All, Is there a simple way (or already an existing list) to extract/parse from the heterodictionaries or monomer libraries which 3-letter symbols are actually modified standard amino acids (as compared to bona fide ligands, solvent molecules etc)? Thx!! BR ----------------------------------------------------------------- Bernhard Rupp 001 (925) 209-7429 +43 (676) 571-0536 [log in to unmask] [log in to unmask] http://www.ruppweb.org/ ------------------------------------------------------------------ Knowledge: When you know a thing, to know that you know it, and when you do not know a thing, to recognize that you do not know it. Conficius. ------------------------------------------------------------------