code: @Override
  	public void setPDBName(String s) {
  		// hetatoms can have pdb_name length < 3. e.g. CU (see 1a4a position 1200 )
  		//if (s.length() != 3) {
  		//throw new PDBParseException("amino acid name is not of length 3!");
  		//}
  		if (s != null && s.equals("?")) logger.info("invalid pdbname: ?");
  		pdb_name =s ;
  
  	}
docs: Set three character name of Group .
  
  @param s  a String specifying the PDBName value
  @see #getPDBName