The linking groups provide {HEAD ~ adequate distance} between the dye and {TAIL ~ the biomolecule} for efficient attachment without imparting excessive hydrophobicity 
between
The linking groups provide { HEAD ~ adequate distance } between the dye and { TAIL ~ the biomolecule } for efficient attachment without imparting excessive hydrophobicity
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH