title: Synthesis and structural characterization of stable branched DNA g-quadruplexes using the trebler phosphoramidite.
abstract: Guanine (G)-rich sequences can form a noncanonical four-stranded structure known as the G-quadruplex. G-quadruplex structures are interesting because of their potential biological properties and use in nanosciences. Here, we describe a method to prepare highly stable G-quadruplexes by linking four G-rich DNA strands to form a monomolecular G-quadruplex. In this method, one strand is synthesized first, and then a trebler molecule is added to simultaneously assemble the remaining three strands. This approach allows the introduction of specific modifications in only one of the strands. As a proof of concept, we prepared a quadruplex where one of the chains includes a change in polarity. A hybrid quadruplex is observed in ammonium acetate solutions, whereas in the presence of sodium or potassium, a parallel G-quadruplex structure is formed. In addition to the expected monomolecular quadruplexes, we observed the presence of dimeric G-quadruplex structures. We also applied the method to prepare G-quadruplexes containing a single 8-aminoguanine substitution and found that this single base stabilizes the G-quadruplex structure when located at an internal position.
authors.affiliation: Department of Chemical and Biomolecular Nanotechnology, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Networking Centre on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) Jordi Girona 18-26, 08034 Barcelona (Spain) ; Department of Chemistry and Molecular Pharmacology, Institute for Research in Biomedicine (IRB Barcelona) Baldiri i Reixac 10, 08028 Barcelona (Spain).
authors.forename: Rubén
authors.initials: R
authors.lastname: Ferreira
authors.affiliation: Department of Chemical and Biomolecular Nanotechnology, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Networking Centre on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) Jordi Girona 18-26, 08034 Barcelona (Spain) ; Department of Chemistry and Molecular Pharmacology, Institute for Research in Biomedicine (IRB Barcelona) Baldiri i Reixac 10, 08028 Barcelona (Spain).
authors.forename: Margarita
authors.initials: M
authors.lastname: Alvira
authors.affiliation: Department of Chemical and Biomolecular Nanotechnology, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Networking Centre on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) Jordi Girona 18-26, 08034 Barcelona (Spain) ; Department of Chemistry and Molecular Pharmacology, Institute for Research in Biomedicine (IRB Barcelona) Baldiri i Reixac 10, 08028 Barcelona (Spain).
authors.forename: Anna
authors.initials: A
authors.lastname: Aviñó
authors.affiliation: Departmento de Química Física Biológica, Instituto de Química Física 'Rocasolano' CSIC, Serrano 119, 28006 Madrid (Spain).
authors.forename: Irene
authors.initials: I
authors.lastname: Gómez-Pinto
authors.affiliation: Departmento de Química Física Biológica, Instituto de Química Física 'Rocasolano' CSIC, Serrano 119, 28006 Madrid (Spain).
authors.forename: Carlos
authors.initials: C
authors.lastname: González
authors.affiliation: Department of Chemistry, University of Liège Allée de la Chimie Building B6c, 4000 Liège (Belgium).
authors.forename: Valérie
authors.initials: V
authors.lastname: Gabelica
authors.affiliation: Department of Chemical and Biomolecular Nanotechnology, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Networking Centre on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) Jordi Girona 18-26, 08034 Barcelona (Spain) ; Department of Chemistry and Molecular Pharmacology, Institute for Research in Biomedicine (IRB Barcelona) Baldiri i Reixac 10, 08028 Barcelona (Spain).
authors.forename: Ramon
authors.initials: R
authors.lastname: Eritja
keywords: 8-aminoguanines; DNA structures; G-quadruplexs; branched oligonucleotides; oligonucleotides