title: Chemical synthesis of LNA-2-thiouridine and its influence on stability and selectivity of oligonucleotide binding to RNA.
abstract: Hybridization to RNA is important for many applications, including antisense therapeutics, RNA interference, and microarray screening. Similar thermodynamic stabilities of A-U and G-U base pairs result in difficulties in selective binding to RNA. Moreover, A-U pairs are weaker than G-C pairs so that binding is sometimes weak when many A-U pairs are present. It is known, however, that replacement of uridine with 2-thiouridine significantly improves binding and selectivity. To test for additional improvement of binding and of the specificity for binding A over G, LNA-2-thiouridine was synthesized for the first time and incorporated into many LNA-2'-O-methyl-RNA/RNA duplexes. UV melting was used to measure the thermodynamic effect of replacing 2'-O-methyluridine with 2'-O-methyl-2-thiouridine or LNA-2-thiouridine. The 2-thiouridine usually enhances binding and selectivity. Selectivity is optimized when a single 2-thiouridine is placed at an internal position in a duplex.
authors.affiliation: Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704 Poznan, Noskowskiego 12/14, Poland.
authors.forename: Marta
authors.initials: M
authors.lastname: Carlucci
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Kierzek
authors.forename: Anna
authors.initials: A
authors.lastname: Olejnik
authors.forename: Douglas H
authors.initials: DH
authors.lastname: Turner
authors.forename: Ryszard
authors.initials: R
authors.lastname: Kierzek
mesh_terms: D009693:Nucleic Acid Hybridization; D009711:Nucleotides / Q000737:chemistry*; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000737:chemistry*; D011721:Pyrenes / Q000737:chemistry; D012313:RNA / Q000138:chemical synthesis / Q000737:chemistry*; D012330:RNA, Double-Stranded / Q000737:chemistry*; D012266:Ribose / Q000031:analogs & derivatives* / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics; D013891:Thiouridine / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000737:chemistry; D044366:Transition Temperature; D014529:Uridine / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: C434798:2'-O-4'-C-methylene-ribofuranosyl nucleotide; C105273:2-thiouridine; D009711:Nucleotides; D009841:Oligonucleotides; D011721:Pyrenes; D012330:RNA, Double-Stranded; D013891:Thiouridine; D012313:RNA; D012266:Ribose; C030984:pyrene; D014529:Uridine