5650
SAR beyond protein - ligand interactions : By combining structure - affinity relationships , protein - ligand modeling studies , and quantum mechanical calculations , we show that ligand conformational energies and basicity play critical roles in ligand binding to the histamine H4 receptor , a GPCR that plays a key role in inflammation .
 Chemical: histamine
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: histamine