Phosphoramidite for the incorporation of an (otherwise unmodified) reverse (5’ to 3’) dA nucleobase within an oligonucleotide.
Modifications for Nuclease Resistance
Protect your oligos from degradation in cell culture or in vivo by incorporating modifications for nuclease resistance with our phosphoramidites and solid supports.
In biological environments, synthetic oligonucleotides, just like their natural counterparts, are prone to degradation due to the presence of exo and endonucleases. You can limit or mitigate this susceptibility, which is particularly important for antisense or RNAi applications, by incorporating nuclease-resistant modifications into oligonucleotides during synthesis.
LGC, Biosearch Technologies manufactures a range of phosphoramidites with protecting group strategies compatible with the usual DNA and RNA chemistries. Additionally, we offer CPGs with a variety of pore sizes and linkers consistent with our unmodified DNA and RNA CPG products.
The most commonly used modification for nuclease resistance is 2’-OMe, which naturally occurs on small RNAs. Synthesizing oligonucleotides that contain 2’-OMe modifications can prevent degradation by nucleases while also increasing binding affinity for its target, making it particularly useful in antisense oligonucleotides.
2’-fluoro bases contain a fluorine-modified ribose, increasing binding affinity and making them more resistant to nucleases compared with unmodified RNA. Additionally, siRNA synthesized with 2’-F pyrimidine nucleosides are more inhibitory, and show considerably increased stability in human plasma, compared to siRNA.
Generally, oligonucleotides hybridise to a RNA oligonucleotide in the following order of increasing stability: DNA < RNA < 2’-OMe-RNA < 2’-F-RNA.
There are several other oligonucleotide modifications you can use to introduce nuclease resistance. The ideal modification is based on several factors, such as where your oligos are most vulnerable (e.g., 3’ or 5’ terminus) and what you need to bind to (i.e., how will the modification affect affinity).