title: Locked nucleoside analogues expand the potential of DNAzymes to cleave structured RNA targets.
abstract: BACKGROUND
  DNAzymes cleave at predetermined sequences within RNA. A prerequisite for cleavage is that the DNAzyme can gain access to its target, and thus the DNAzyme must be capable of unfolding higher-order structures that are present in the RNA substrate. However, in many cases the RNA target sequence is hidden in a region that is too tightly structured to be accessed under physiological conditions by DNAzymes.
  
  
  RESULTS
  We investigated how incorporation of LNA (locked nucleic acid) monomers into DNAzymes improves their ability to gain access and cleave at highly-structured RNA targets. The binding arms of DNAzymes were varied in length and were substituted with up to three LNA and alpha-L-LNA monomers (forming LNAzymes). For one DNAzyme, the overall cleavage reaction proceeded fifty times faster after incorporation of two alpha-L-LNA monomers per binding arm (kobs increased from 0.014 min-1 to 0.78 min-1).
  
  
  CONCLUSIONS
  The data demonstrate how hydrolytic performance can be enhanced by design of LNAzymes, and indicate that there are optimal lengths for the binding arms and for the number of modified LNA monomers.
authors.affiliation: The Nucleic Acid Center, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark. b.vester@bmb.sdu.dk
authors.forename: Birte
authors.initials: B
authors.lastname: Vester
authors.forename: Lykke H
authors.initials: LH
authors.lastname: Hansen
authors.forename: Lars Bo
authors.initials: LB
authors.lastname: Lundberg
authors.forename: B Ravindra
authors.initials: BR
authors.lastname: Babu
authors.forename: Mads D
authors.initials: MD
authors.lastname: Sørensen
authors.forename: Jesper
authors.initials: J
authors.lastname: Wengel
authors.forename: Stephen
authors.initials: S
authors.lastname: Douthwaite
mesh_terms: D001483:Base Sequence; D021881:DNA, Catalytic / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D009841:Oligonucleotides; D016376:Oligonucleotides, Antisense / Q000737:chemistry*; D012313:RNA / Q000737:chemistry / Q000378:metabolism*
chemical_list: D021881:DNA, Catalytic; D009841:Oligonucleotides; D016376:Oligonucleotides, Antisense; C477371:locked nucleic acid; D012313:RNA