def pmvAtomStrip(atom, mol_name = None):
    """ transform PDB(QT) atoms to PMV syntax
      "ATOM    455  N   GLY A  48      -2.978   5.488   6.818  1.00 11.64    -0.351 N" (xJ1_xtal)
            |
           \./
            '  
       xJ1_xtal:A:GLY48:N
    """
    chain = atom[21].strip()
    res_name = atom[16:21].strip()
    res_num = atom[22:26].strip()
    atom = atom[12:16].strip()
    if not mol_name:
        return "%s:%s%s:%s" % (chain, res_name, res_num, atom)
    else:
        return "%s:%s:%s%s:%s" % (mol_name, chain, res_name, res_num, atom)