Box B lies 21 amino acids C terminal to {HEAD ~ Box A} from {TAIL ~ amino acids} 43 139 
from
Box B lies 21 amino acids C terminal to { HEAD ~ Box A } from { TAIL ~ amino acids } 43 139
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH