I have included a part of a structure in this Email. In January Elaine Meng communicated with me about how to color an individual atom in an amino acid that is shown as a ball and stick. So you see I have colored an oxygen atom red in a threonine residue that is part of a peptide that is bound to the protein that is mainly shown as a ribbon structure. Note the Glutamic acid residue shown only as a stick and colored lime green. The peptide backbone of this residue which is in a ribbon representation is also colored lime green So question #1, how can I just color the side chain and not the peptide bond which is in the ribbon. I want to keep the ribbon a continuous blue. Note the Aspartic acid residue that is part of pink ribbon and represented as a ball and stick. So I want to color the side chain the same lime green, I know how to do that, but again the ribbon part of that Asp will also be lime green. Even if all I want is to have one of the oxygen atoms of the side chain colored red, I can do that as well except that the ribbon portion, the peptide bond also is colored red. Question #2: There is a metal ion colored light blue or cyan, How can I get rid of the four short dashed lines that link it to the aforementioned Glu and Asp, as well as another Asp residue? Thank you for your assistance. Arthur G. Szabo Professor Emeritus Wilfrid Laurier University.