In certain embodiments, {TAIL ~ X4} is selected from {HEAD ~ D proline}, D arginine and D phenylalanine 
In certain embodiments , { TAIL ~ X4 } is selected from { HEAD ~ D proline } , D arginine and D phenylalanine
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH