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LNA
is a novel type of nucleic acid analog that contains a 2'-O, 4'-C
methylene bridge. This bridge restricts the flexibility of the
ribofuranose ring and locks the structure into a rigid bicyclic formation,
conferring enhanced hybridization performance and exceptional biostability.
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The LNA Advantage
Duplexes including LNA oligonucleotides are considerably more thermally
stable than similar duplexes constituted from DNA or RNA oligonucleotides,
conferring the following advantages:
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Increased
melting temperature of the oligonucleotide duplex - by 3 to 8 °C per
incorporated LNA nucleoside in the oligomer
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Dramatically
enhanced affinity towards complementary DNA or RNA
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Superior
discrimination between matched and mismatched target nucleic acids
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Hypridization
to complementary nucleic acids, even under low salt conditions and in
the presence of chaotropic agents
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Increased
stability of the oligonucleotide in biological fluids
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Strand
invasion capability
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LNA
oligonucleotides can be applied to almost all platforms that employ
synthetic oligonucleotides:
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Hybridization
probes for the detection of nucleic acids and genotyping e.g.
Molecular Beacons probes, Padlock probes, TaqMan®
probes and probes for in situ hybridization
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Capture
probes for target enrichment, sample preparation and affinity
chromatography
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Allele-specific
PCR1
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Target
validation through antisense technology and siRNA
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Oligonucleotides
for therapeutic applications, such as antisense oligonucleotides,
aptamers, ribozymes, decoy oligonucleotides and siRNA
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Analytical
Specifications of LNA Phosphoramidites
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Test
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locA(bz)
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locMeC(bz)
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locG(ib)
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locT
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31P-NMR
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>
98%
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>
98%
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>
98%
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>
98%
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RP-HPLC
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>
98.0%
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>
98.0%
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>
98.0%
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>
98.0%
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Coupling
efficiency
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>
98.0%
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>
98.0%
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>
98.0%
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>
98.0%
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Key
Features of LNA Phosphoramidites and LNA CPG
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LNA
oligonucleotides are prepared by phosphoramidite chemistry.
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Standard
DNA synthesizer platforms can be employed. No change is required in
the reagents commonly used for DNA synthesis.
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To
further enhance the hybridization characteristics of LNA,
5-methyl-cytidine is employed instead of cytidine.
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LNA
monomers are as soluble in acetonitrile as their DNA counterparts
(except for the 5-methyl-cytidine derivative, which requires the
application of 10-20% dichloromethane as a co-solvent).
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Mixmer
oligonucleotides containing LNA, DNA and/or RNA monomers can be
assembled easily.
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LNA
oligonucleotides with predefined melting temperatures (Tm)
can be designed and prepared.
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Oligonucleotides
containing LNA can also include modifications and non-radioactive
labels, similar to DNA oligonucleotides.
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LNA
oligonucleotides can be phosphorothioated by standard procedures.
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LNA
CPG can be employed in the same manner as DNA CPG, without any change
in procedures.
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In most respects, LNA may be handled like DNA: it
is soluble in aqueous buffers, can be ethanol precipitated, dried and
resuspended, and can be analyzed by gel electrophoresis, HPLC and
MALDI-TOF.
The synthesis of LNA oligonucleotides is
similar to DNA oligonucleotide synthesis, but with an elongated coupling
time of 8 minutes. Deprotection should be conducted with aqueous ammonia,
since the C-derivative is protected with the conventional benzoyl
protective group. Fast-deprotecting reagents, such as methylamine, should
be avoided. |
locT Phosphoramidite |
locA(bz) Phosphoramidite |
locG(ib) Phosphoramidite |
locMeC(bz) Phosphoramidite |
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LNA Phosphoramidites
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PE 8900 and Polygen
compatible
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0.25gx1
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1gx1
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locA(bz)
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AL11481-01
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AL11483-01
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locMeC(bz)
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CL11481-01
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CL11483-01
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locG(ib)
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GL11481-01
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GL11483-01
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locT
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TL11481-01
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TL11483-01
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1oz
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20/400 screw-cap bottle
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ABI compatible
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0.25gx1
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1gx1
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locA(bz)
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AL11431-01
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AL11433-01
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locMeC(bz)
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CL11431-01
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CL11433-01
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locG(ib)
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GL11431-01
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GL11433-01
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locT
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TL11431-01
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TL11433-01
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15ml
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septum bottle
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Controlled Pore Glass and Columns
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PE 8900 compatible
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CPG 500Åx4
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50nmol
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0.2µmol
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1µmol
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locA(bz)
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A611404-01
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A621404-01
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A631404-01
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locMeC(bz)
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C611404-01
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C621404-01
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C631404-01
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locG(ib)
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G611404-01
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G621404-01
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G631404-01
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locT
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T611404-01
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T621404-01
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T631404-01
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CPG 1000Åx4
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50nmol
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0.2µmol
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1µmol
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locA(bz)
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A711404-01
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A721404-01
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A731404-01
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locMeC(bz)
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C711404-01
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C721404-01
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C731404-01
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locG(ib)
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G711404-01
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G721404-01
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G731404-01
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locT
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T711404-01
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T721404-01
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T731404-01
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Bulk CPG
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500Å loading
30-40µmol/g
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1000Å loading
25-35µmol/g
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1g
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1g
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locA(bz)
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A601401-01
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A701401-01
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locMeC(bz)
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C601401-01
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C701401-01
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locG(ib)
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G601401-01
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G701401-01
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locT
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T601401-01
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T701401-01
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