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