{HEAD ~ each} of {TAIL ~ Am} is independently a moiety based on an amino acid or on an amino acid derivative, or on a number of amino acids or derivatives thereof 
of
{ HEAD ~ each } of { TAIL ~ Am } is independently a moiety based on an amino acid or on an amino acid derivative , or on a number of amino acids or derivatives thereof
HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH