PyMOL

PyMOL is a molecular viewer, render tool, 3D molecular editor developed in the spirit of RasMol and OpenRasMol and intended for visualization of 3D chemical structures including atomic resolution X-ray crystal structures of: proteins, nucleic acids (DNA, RNA, & tRNA), and carbohydrates, as well as small molecule structures of drug leads, inhibitors, metabolites, sugars, nucleoside phosphates, and other ligands including inorganic salts and solvent molecules.