title: Assembling of G-strands into novel tetra-molecular parallel G4-DNA nanostructures using avidin-biotin recognition.
abstract: We describe a method for the preparation of novel long (hundreds of nanometers), uniform, inter-molecular G4-DNA molecules composed of four parallel G-strands. The only long continuous G4-DNA reported so far are intra-molecular structures made of a single G-strand. To enable a tetra-molecular assembly of the G-strands we developed a novel approach based on avidin-biotin biological recognition. The steps of the G4-DNA production include: (i) Enzymatic synthesis of long poly(dG)-poly(dC) molecules with biotinylated poly(dG)-strand; (ii) Formation of a complex between avidin-tetramer and four biotinylated poly(dG)-poly(dC) molecules; (iii) Separation of the poly(dC) strands from the poly(dG)-strands, which are connected to the avidin; (iv) Assembly of the four G-strands attached to the avidin into tetra-molecular G4-DNA. The average contour length of the formed structures, as measured by AFM, is equal to that of the initial poly(dG)-poly(dC) molecules, suggesting a tetra-molecular mechanism of the G-strands assembly. The height of tetra-molecular G4-nanostructures is larger than that of mono-molecular G4-DNA molecules having similar contour length. The CD spectra of the tetra- and mono-molecular G4-DNA are markedly different, suggesting different structural organization of these two types of molecules. The tetra-molecular G4-DNA nanostructures showed clear electrical polarizability. This suggests that they may be useful for molecular electronics.
authors.affiliation: Department of Biochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, 69978.
authors.forename: Natalia
authors.initials: N
authors.lastname: Borovok
authors.forename: Natalie
authors.initials: N
authors.lastname: Iram
authors.forename: Dragoslav
authors.initials: D
authors.lastname: Zikich
authors.forename: Jamal
authors.initials: J
authors.lastname: Ghabboun
authors.forename: Gideon I
authors.initials: GI
authors.lastname: Livshits
authors.forename: Danny
authors.initials: D
authors.lastname: Porath
authors.forename: Alexander B
authors.initials: AB
authors.lastname: Kotlyar
mesh_terms: D001360:Avidin / Q000737:chemistry* / Q000648:ultrastructure; D001710:Biotin / Q000737:chemistry*; D002942:Circular Dichroism; D054856:G-Quadruplexes; D018625:Microscopy, Atomic Force; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D011066:Poly C / Q000737:chemistry; D011068:Poly G / Q000737:chemistry; D011089:Polydeoxyribonucleotides / Q000737:chemistry*; D055672:Static Electricity
chemical_list: D011089:Polydeoxyribonucleotides; D001360:Avidin; D011068:Poly G; C023826:poly(dC); C026628:poly(dG); D011066:Poly C; D001710:Biotin