22934
Analysis of the surface properties of the protein identifies an extensive patch of negative electrostatic potential on the exposed surface of one of the beta - sheets , which likely forms a binding site for a ligand or interaction partner .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None