It is not clear if {HEAD ~ these two highly conserved amino acids} play {TAIL ~ a role} in C C chemokine activity since they are not predicted to contact the receptor 
It is not clear if { HEAD ~ these two highly conserved amino acids } play { TAIL ~ a role } in C C chemokine activity since they are not predicted to contact the receptor
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH