title: Macromolecule backbone models.
mesh_terms: D046911:Macromolecular Substances; D008958:Models, Molecular; D011487:Protein Conformation; D012259:Ribonuclease, Pancreatic; D012260:Ribonucleases
chemical_list: D046911:Macromolecular Substances; D012260:Ribonucleases; D012259:Ribonuclease, Pancreatic; C022542:ribonuclease S