Note: an alternative is to use the RCSB API e.g. http://www.rcsb.org/pdb/rest/hmmer?structureId=1cdg.

def get_pfam_accession_numbers_from_pdb_id(self, pdb_id):
        '''Note: an alternative is to use the RCSB API e.g. http://www.rcsb.org/pdb/rest/hmmer?structureId=1cdg.'''
        pdb_id = pdb_id.lower()
        if self.pdb_chain_to_pfam_mapping.get(pdb_id):
            return self.pdb_chain_to_pfam_mapping[pdb_id].copy()