Biomedical subjects
Publications and source records attributed to Poul Nielsen.
A novel class of 3',4'-trans-linked bicyclic nucleosides with locked S-type furanose conformations is introduced by synthesis of two model derivatives; one was obtained by cyclic ether formation and the other by ring-closing metathesis methodology.
Alpha-LNA is presented as a stereoisomer of LNA (locked nucleic acid) with alpha-D-configuration. Three different approaches towards the thymine alpha-LNA monomer as well as the 5-methylcytosine alpha-LNA monomer are presented. Different alpha-LNA sequences have been synthesised and their hybridisation with complementary DNA and RNA has been evaluated by means of thermal stability experiments and circular dichroism spectroscopy. In a mixed pyrimidine sequence, alpha-LNA displays unprecedented parallel-stranded and selective RNA binding. Furthermore, a remarkable selectivity for hybridisation with RNA over DNA is indicated.
Ring-closing metathesis (RCM) is applied as a new and powerful technology in the construction of nucleoside analogues that are conformationally restricted in S-type conformations due to additional 3',4'- and/or 3',5'-linkages.
Cyclic dinucleotides with saturated connections between a nucleobase and the phosphate are synthesised using a tandem ring-closing metathesis (RCM) and hydrogenation protocol and found to be significantly stabilised towards ammonia.
Two pyrimidine alpha-LNA nucleoside monomers have been synthesised and incorporated into alpha-configured oligonucleotides. A fully modified mixed alpha-LNA sequence displays unprecedented parallel stranded hybridisation with complementary RNA and a remarkable selectivity for RNA over DNA. Modelling shows alpha-LNA:RNA to form an extended duplex with a very broad major groove.