In other embodiments, {HEAD ~ X2} is selected from D leucine, D valine, {TAIL ~ glycine} and D proline 
is selected from
In other embodiments , { HEAD ~ X2 } is selected from D leucine , D valine , { TAIL ~ glycine } and D proline
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL REL OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH