Figure 1.

(A) Structural illustration of a chemically modified siRNA-GalNAc conjugate duplex. Black: 2′-O-methyl (2′-OMe), green: 2′-deoxy-2′-fluoro (2′-F), orange lines: phosphorothioate linkage (PS). (B) Structures of the native nucleotides and standard modified nucleotides mentioned in this study, including 2′-OMe and 2′-F. (C) Backbone chemistries include both natural phosphate (PO) and phosphorothioate (PS; orange lines in A). (D) Representative 4′- and 5′ modifications studied in our laboratories with 2′-modifications.