5300
We identified a stretch of 23 amino acids , rich in serine and threonine residues , which was responsible for most of the repression activity.
 None
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: RNA,cell type,protein,cell line,DNA, Arguments type: . 
Text: {0} 
Answer:
 None