SiRNA carrying an (E)-vinylphosphonate moiety at the 5΄ end of the guide strand augments gene silencing by enhanced binding to human Argonaute-2.

ABSTRACT: Efficient gene silencing by RNA interference (RNAi) in vivo requires the recognition and binding of the 5΄- phosphate of the guide strand of an siRNA by the Argonaute protein. However, for exogenous siRNAs it is limited by the rapid removal of the 5΄- phosphate of the guide strand by metabolic enzymes. Here, we have determined the crystal structure of human Argonaute-2 in complex with the metabolically stable 5΄-(E)-vinylphosphonate (5΄-E-VP) guide RNA at 2.5-Å resolution. The structure demonstrates how the 5΄ binding site in the Mid domain of human Argonaute-2 is able to adjust the key residues in the 5΄-nucleotide binding pocket to compensate for the change introduced by the modified nucleotide. This observation also explains improved binding affinity of the 5΄-E-VP -modified siRNA to hu

SUBMITTER: Elkayam E 

PROVIDER: S-EPMC5389677 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature