In other embodiments, {TAIL ~ X4} is selected from {HEAD ~ a neutral D amino acid}, a positively charged D amino acid and an aromatic D amino acid 
In other embodiments , { TAIL ~ X4 } is selected from { HEAD ~ a neutral D amino acid } , a positively charged D amino acid and an aromatic D amino acid
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH