3753
Molecular docking studies revealed a binding pocket for the ATP derivatives that is bordered by transmembrane helices 3 , 5 , 6 , and 7 in human P2Y ( 12 , ) with Y ( 105 ) , E ( 188 ) , R ( 256 ) , Y ( 259 ) , and K ( 280 ) playing a particularly important role in ligand interaction .
 Chemical: ATP
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: ATP