Amino acids attached to 2′-amino-LNA: synthesis and excellent duplex stability

MW Johannsen, L Crispino, MC Wamberg… - Organic & …, 2011 - pubs.rsc.org
MW Johannsen, L Crispino, MC Wamberg, N Kalra, J Wengel
Organic & biomolecular chemistry, 2011pubs.rsc.org
The synthesis of 2′-amino-LNA (the 2′-amino derivative of locked nucleic acid) has
opened up a number of exciting possibilities with respect to modified nucleic acids. While
maintaining the excellent duplex stability inferred by LNA-type oligonucleotides, the nitrogen
in the 2′-position of 2′-amino-LNA monomers provides an excellent handle for
functionalisation. Herein, the synthesis of amino acid functionalised 2′-amino-LNA
derivatives is described. Following ON synthesis, a glycyl unit attached to the N2′-position …
The synthesis of 2′-amino-LNA (the 2′-amino derivative of locked nucleic acid) has opened up a number of exciting possibilities with respect to modified nucleic acids. While maintaining the excellent duplex stability inferred by LNA-type oligonucleotides, the nitrogen in the 2′-position of 2′-amino-LNA monomers provides an excellent handle for functionalisation. Herein, the synthesis of amino acid functionalised 2′-amino-LNA derivatives is described. Following ON synthesis, a glycyl unit attached to the N2′-position of 2′-amino-LNA monomers was further acylated with a variety of amino acids. On binding to DNA/RNA complements, the modified ONs induce a marked increase in thermal stability, which is particularly apparent in a buffer system with a low salt concentration. The increase in thermal stability is thought to be caused, at least in part, by decreased electrostatic repulsion between the negatively charged phosphate backbones when positively charged amino acid residues are appended. Upon incorporation of more than one 2′-amino-LNA modification, the effects are found to be nearly additive. For comparison, 2′-amino-LNA derivatives modified with uncharged groups have been synthesised and their effect on duplex thermal stability likewise investigated.
The Royal Society of Chemistry