2'-O,4'-C-methylene-bridged ribose
Locked nucleic acid
Gapmers with short high-affinity wings, and mixmers
A locked nucleic acid nucleotide is a ribonucleotide in which a methylene bridge joins the 2'-oxygen to the 4'-carbon of the sugar. The bridge locks the ribose in the C3'-endo conformation of RNA, so the nucleotide is pre-organized for hybridization: each locked residue raises the melting temperature of the duplex with complementary RNA, per modification, more than either 2'-MOE or 2'-OMe does.
Like the other 2'-modified sugars, a locked residue is not a substrate for RNase H, so a knockdown design is a gapmer with locked wings and a DNA gap. Locked residues also resist nucleases. A design with no gap, in which locked and DNA residues alternate, is a steric blocker, a form used for microRNA inhibition and splice switching.
Order this chemistry
Designed using the AUMsilence platform against the target, or made to the supplied sequence by quotation.
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Use
Applications and selection
Affinity in a short oligonucleotide
Where the accessible window on the target is short, or the region is structured, a few locked residues give the affinity that would otherwise need a longer oligonucleotide.
A published design, reproduced
Published gapmers and microRNA inhibitors built on locked nucleic acid are made to the same pattern, position by position.
Affinity per modification
Of the three chemistries sold here, locked nucleic acid raises duplex stability the most per residue, so a design needs the fewest modified positions.
What it is not used for
A knockdown design carrying locked residues at every position: such an oligonucleotide leaves no gap for RNase H.
Design
Design notes
Short wings. Locked wings are kept to a few residues at each end, for two reasons. A locked residue adds so much affinity that a few of them reach the melting temperature the design needs, and a longer wing adds affinity it does not need. That excess is a cost rather than a gain. An oligonucleotide that hybridizes very tightly can hold on to a partially matched sequence elsewhere in the transcriptome, so extra locked residues raise the risk of off-target effects without adding activity the design needs.
The gap. The central run of unmodified deoxynucleotides is what RNase H1 cleaves opposite. Keep it DNA and keep it long enough for the enzyme; a locked residue inside the gap blocks cleavage at that position. Write out which positions are locked and which are DNA when you send the sequence.
The backbone. Gapmers are typically made on a phosphorothioate backbone, which resists nucleases and binds proteins, supporting uptake into cells and tissue, and which lowers the affinity of the duplex slightly. At high concentration a phosphorothioate backbone can also raise toxicity.
Mixmers. For steric block and microRNA inhibition, locked residues are spread through the oligonucleotide and alternated with DNA, so there is no gap and no RNase H cleavage. The oligonucleotide occupies its site.
Purification and yields
Purification and study model
Desalt and RPC are sold for cellular studies. HPLC, the grade bought for primary cells and animal models, is sold for in vitro and in vivo studies.
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| Purification | Study model |
|---|---|
| desalt | in vitro, cellular studies |
| RPC | in vitro, cellular studies |
| HPLC | in vitro and in vivo |
This chemistry is sold at every yield in every tier, so the tier and the yield are chosen independently.
Related
Beside this chemistry
- 2'-MOEThe conventional-length gapmer chemistry
- 2'-OMeSteric block, splice switching and microRNA inhibition
- AUMsilence
sdASOmRNA knockdown designed by the platform, no transfection reagent - AUMantagomir
sdASOmicroRNA inhibition designed by the platform, no transfection reagent - Bulk synthesisAbove 1000 nmol, further modifications
For research use only. Not for use in diagnostic or therapeutic procedures.