title: G-quadruplexes are specifically recognized and distinguished by selected designed ankyrin repeat proteins.
abstract: We introduce designed ankyrin repeat binding proteins (DARPins) as a novel class of highly specific and structure-selective DNA-binding proteins, which can be functionally expressed within all cells. Human telomere quadruplex was used as target to select specific binders with ribosome display. The selected DARPins discriminate the human telomere quadruplex against the telomeric duplex and other quadruplexes. Affinities of the selected binders range from 3 to 100 nM. CD studies confirm that the quadruplex fold is maintained upon binding. The DARPins show different specificity profiles: some discriminate human telomere quadruplexes from other quadruplex-forming sequences like ILPR, c-MYC and c-KIT, while others recognize two of the sequences tested or even all quadruplexes. None of them recognizes dsDNA. Quadruplex-binding DARPins constitute valuable tools for specific detection at very small scales and for the in vivo investigation of quadruplex DNA.
authors: Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland.
authors: Oliver
authors: O
authors: Scholz
authors: Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland.
authors: Simon
authors: S
authors: Hansen
authors: Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland plueckthun@bioc.uzh.ch.
authors: Andreas
authors: A
authors: Plückthun
mesh_terms: D017089:Ankyrin Repeat; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D054856:G-Quadruplexes; D006801:Humans; D015202:Protein Engineering; D016615:Telomere / Q000737:chemistry
chemical_list: D004268:DNA-Binding Proteins; D004247:DNA