Locked nucleic acid

A locked nucleic acid (LNA), often referred to as inaccessible RNA, is a modified RNA nucleotide. The ribose moiety of an LNA nucleotide is modified with an extra bridge connecting the 2' and 4' carbons. The bridge "locks" the ribose in the 3'-endo structural conformation, which is often found in the A-form of DNA or RNA. LNA nucleotides can be mixed with DNA or RNA bases in the oligonucleotide whenever desired. Such oligomers are commercially available. The locked ribose conformation enhances base stacking and backbone pre-organization. This significantly increases the thermal stability (melting temperature) of oligonucleotides. [cite journal
title=Thermodynamic, Counterion, and Hydration Effects for the Incorporation of Locked Nucleic Acid Nucleotides into DNA Duplexes
author=Kaur, H.
coauthors=Arora, A.; Wengel, J.; Maiti, S.
journal=Biochemistry
year=2006
volume=45
issue=23
pages=7347–55
doi=10.1021/bi060307w ]

LNA nucleotides are used to increase the sensitivity and specificity of expression in DNA microarrays, FISH probes, real-time PCR probes and other molecular biology techniques based on oligonucleotides. For the "in situ" detection of miRNA the use of LNA is currently (2005) the only efficient method. A triplet of LNA nucleotides surrounding a single-base mismatch site maximizes LNA probe specificity unless the probe contains the guanine base of G-T mismatch. [cite journal
author=You Y.
coauthors=Moreira B.G.; Behlke M.A. and Owczarzy R.
year=2006
title=Design of LNA probes that improve mismatch discrimination
journal=Nucleic Acids Res.
volume=34
issue=8
doi=10.1093/nar/gkl175
url=http://nar.oxfordjournals.org/cgi/reprint/34/8/e60?ijkey=IqLeijzpwQHCzit&keytype=ref |pages=e60
pmid=16670427]

References

External links

* [http://lnatools.com A predictor for the physical properties of LNA modified oligonucleotides]
* [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15491130 LNA (locked nucleic acid): high-affinity targeting of complementary RNA and DNA]
* [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12573856 LNA: a versatile tool for therapeutics and genomics]
* [http://pubs.acs.org/cgi-bin/sample.cgi/nalefd/2005/5/i01/abs/nl048246f.html Alternative Nucleic Acid Analogues for Programmable Assembly: Hybridization of LNA to PNA]