{HEAD ~ Yields} of {TAIL ~ virus} like particles derived from those optimized HPV L1 genes are high 
of
{ HEAD ~ Yields } of { TAIL ~ virus } like particles derived from those optimized HPV L1 genes are high
HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH