Specify scheme to color the atoms by. Default is
"default". Other choies are "Carbon", ssPyMOL", "ssJmol", "Jmol",
"default", "amino",
"shapely", "nucleic", "chain", "chainHetatm", "prop".
color
Fixed coloring, overrides colorScheme.
opacity
Opacity, must be the same for all atoms in the model.