The term LNA (locked nucleic acid) refers to any oligonucleotide containing one or more LNA monomer(s). An LNA monomer (se structure below) contains an O2'-C4’-methylene-linked bicyclic ribose unit that is locked in an RNA-like conformation. LNA is thus a structural mimic of RNA.
LNA oligonucleotides are synthesized by conventional automated synthesis to give fully modified LNA, LNA-modified DNA, LNA-modified RNA or, for example, LNA-modified 2’-O-Me-RNA oligonucleotides. The fact that LNA monomers readily can be mixed with a variety of natural or synthetic nucleic acid monomers and labels results in great design flexibility.
LNA oligonucleotides are characterized by its capability to bind to complementary nucleic acids with unprecedented binding affinities as shown below for 9-mer duplexes towards an RNA target (melting temperatures are given; LNA monomers are underlined):
Melting temperatures of duplexes towards RNA target
|DNA||d(GTG ATA TGC)||28°C|
|RNA||r(GUG AUA UGC)||38°C|
|DNA(6)-LNA(3)||d(GTG ATA TGC)||50°C|
|RNA(6)-LNA(3)||r(GTG ATA TGC)||63°C|
|2'-O-Me-RNA(6)-LNA(3)||OMe(GTG ATA TGC)||63°C|
|LNA(9)||(GTG ATA TGC)||73°C|
Other basic physicochemical properties of LNA oligonucleotides are
LNA infomation in Danish http://www.biosite.dk/leksikon/leksikon.htm