6011
In contrast , capsid proteins derived from the P1 precursor with a valine substitution at the amino terminus of VP1 ( VP1 - G001V ) assembled empty capsid particles but were deficient in assembling RNA - containing virions .
 capsid proteins, P1 precursor, VP1, VP1 - G001V
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 capsid proteins, P1 precursor, VP1, VP1 - G001V