Figure 2. Chemical modifications on the nucleic acid backbone increase their nuclease stability.

(A) PS bonds include replacement of non-bridging oxygen with sulfur. (B) 2′OMe are modification of the 2′-position of the ribose with a methyl group. (C) LNA bases contain a methylene bridge between the 2′-O with the 4′-C of the ribose and “locks” the sugar conformation.