{HEAD ~ The one or more purified polypeptides} can be {TAIL ~ about 15 to about 75 amino acids} in length 
{ HEAD ~ The one or more purified polypeptides } can be { TAIL ~ about 15 to about 75 amino acids } in length
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH