7801
Mode of action studies by molecular modeling indicate that the 2 ' - fluoro moiety by hydrogen bond as well as the Van der Waals interaction of the carbocyclic ring with the phenylalanine moiety of the polymerase promote the positive binding , even in the drug - resistant mutants .
 Chemical: 2 ' - fluoro; Chemical: hydrogen; Chemical: carbocyclic; Chemical: phenylalanine
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: 2 ' - fluoro; Chemical: hydrogen; Chemical: carbocyclic; Chemical: phenylalanine