18288
The putative ionic interaction results in the EC - 3 loop pulling over the top ( extracellular side ) of the receptor ; this EC - 3 loop conformation may serve protective and mechanistic roles .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities:  
Answer:
 None