<entity chain_ids="A" class="protein" count="1" entity_id="1" source_entry="1DQM" type="polymer"/>
<entity chain_ids="B" class="protein" count="1" entity_id="2" source_entry="1DQM" type="polymer"/>
<entity chain_ids="C,D" class="water" count="2" entity_id="3" source_entry="1DQM" type="water"/>