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