Question: Which protein interacts with morphine?
Paraphrase: Morphine interacts with which proteins?
SPARQL (Wikidata):  select distinct ?obj where { wd:Q81225 wdt:P129 ?obj . ?obj wdt:P31 wd:Q8054 } 
Answer: Opioid receptor mu 1, Opioid receptor kappa 1, Opioid receptor delta 1