A wrapper function for match_pdb_chains. This function only takes the best match. The return
        value is a dict mapping
            chain_id_in_pdb1 -> None or a tuple (chain_id_in_pdb_2, percentage_identity_score)
       where percentage_identity_score is a float. e.g. 'A' -> ('B', 100).

def match_best_pdb_chains(pdb1, pdb1_name, pdb2, pdb2_name, cut_off = 60.0, use_seqres_sequences_if_possible = True):
    '''A wrapper function for match_pdb_chains. This function only takes the best match. The return
        value is a dict mapping
            chain_id_in_pdb1 -> None or a tuple (chain_id_in_pdb_2, percentage_identity_score)
       where percentage_identity_score is a float. e.g. 'A' -> ('B', 100).'''
    d = match_pdb_chains(pdb1, pdb1_name, pdb2, pdb2_name, cut_off = cut_off, allow_multiple_matches = False, use_seqres_sequences_if_possible = use_seqres_sequences_if_possible)
    for k, v in d.iteritems():
        if v:
            d[k] = v[0]
    return d