I am working on a large multi subunit structure (4CR2). Originally I selected one of the subunits, and received the error message that suggested I should use the split command. Which I did and obviously I must have been successful in splitting the subunits. Each of the subunits is now labelled as being split, i.e. (#0.14) etc. I was successful in showing the surfaces of 4 subunits, and colored them differently. However, when I tried to show the surface of one of the subunits with 437 residues, (several residues cannot be resolved) I received this error message One subunit which I successfully was able to show the surface in the image had 467 residues and also had a large number of residues that were not resolvable. So I am stuck! Your help would be appreciated. AGSzabo