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.jpg): Failed to open stream: No such file or directory in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 117 J+Am+Chem+Soc
2016 ; 138
(28
): 8667-9
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Structure-Guided Control of siRNA Off-Target Effects
#MMPMID27387838
Suter SR
; Sheu-Gruttadauria J
; Schirle NT
; Valenzuela R
; Ball-Jones AA
; Onizuka K
; MacRae IJ
; Beal PA
J Am Chem Soc
2016[Jul]; 138
(28
): 8667-9
PMID27387838
show ga
Short interfering RNAs (siRNAs) are promising therapeutics that make use of the
RNA interference (RNAi) pathway, but liabilities arising from the native RNA
structure necessitate chemical modification for drug development. Advances in the
structural characterization of components of the human RNAi pathway have enabled
structure-guided optimization of siRNA properties. Here we report the 2.3 Å
resolution crystal structure of human Argonaute 2 (hAgo2), a key nuclease in the
RNAi pathway, bound to an siRNA guide strand bearing an unnatural triazolyl
nucleotide at position 1 (g1). Unlike natural nucleotides, this analogue inserts
deeply into hAgo2's central RNA binding cleft and thus is able to modulate
pairing between guide and target RNAs. The affinity of the hAgo2-siRNA complex
for a seed-only matched target was significantly reduced by the triazolyl
modification, while the affinity for a fully matched target was unchanged. In
addition, siRNA potency for off-target repression was reduced (4-fold increase in
IC50) by the modification, while on-target knockdown was improved (2-fold
reduction in IC50). Controlling siRNA on-target versus microRNA (miRNA)-like
off-target potency by projection of substituent groups into the hAgo2 central
cleft from g1 is a new approach to enhance siRNA selectivity with a strong
structural rationale.
|Argonaute Proteins/metabolism
[MESH]
|Class I Phosphatidylinositol 3-Kinases/deficiency/genetics
[MESH]
|Humans
[MESH]
|Nucleotides/chemistry
[MESH]
|RNA Interference
[MESH]
|RNA, Small Interfering/chemistry/*genetics
[MESH]