The method also allows for the identification of nucleic acids that have facilitating {HEAD ~ activities} as measured by {TAIL ~ their ability} to facilitate formation of a covalent bond between the nucleic acid, including its associated functional unit, and its target 
as measured by
The method also allows for the identification of nucleic acids that have facilitating { HEAD ~ activities } as measured by { TAIL ~ their ability } to facilitate formation of a covalent bond between the nucleic acid , including its associated functional unit , and its target
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL 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