Expanding the binding space of argonaute-2: incorporation of either E or Z isomers of 6′-vinylphosphonate at the 5′ end of the antisense strand improves RNAi activity

Both E - and Z - isomers of 6′-vinylphosphonate work as stable phosphate mimic at the 5′ end of the antisense strand and work as efficiently as 5′-( E )-vinylphosphonate in vitro and in vivo .