This is not really protein crystallography but we are trying to model build a ligand into a protein binding site. A similar ligand is already in place and we want to replace this by initially superimposing a phenyl ring which is common to both ligands. We understand that such superpositioning can be done with eg Quanta but do not have access to this program. Does anyone know of a downloadable program that we could use instead?
Rex Palmer Birkbeck College, London
