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Updated: Apr 26, 2026

A G-quadruplex DNA-affinity Approach for Purification of Enzymatically Active G4 Resolvase1
Published on: March 18, 2017
G-quadruplexes are specifically recognized and distinguished by selected designed ankyrin repeat proteins
Oliver Scholz1, Simon Hansen1, Andreas Plückthun2
1Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland.
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.
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