title: X-ray characterization of mesophases of human telomeric G-quadruplexes and other DNA analogues.
abstract: Observed in the folds of guanine-rich oligonucleotides, non-canonical G-quadruplex structures are based on G-quartets formed by hydrogen bonding and cation-coordination of guanosines. In dilute 5'-guanosine monophosphate (GMP) solutions, G-quartets form by the self-assembly of four GMP nucleotides. We use x-ray diffraction to characterize the columnar liquid-crystalline mesophases in concentrated solutions of various model G-quadruplexes. We then probe the transitions between mesophases by varying the PEG solution osmotic pressure, thus mimicking in vivo molecular crowding conditions. Using the GMP-quadruplex, built by the stacking of G-quartets with no covalent linking between them, as the baseline, we report the liquid-crystalline phase behaviors of two other related G-quadruplexes: (i) the intramolecular parallel-stranded G-quadruplex formed by the 22-mer four-repeat human telomeric sequence AG3(TTAG3)3 and (ii) the intermolecular parallel-stranded G-quadruplex formed by the TG4T oligonucleotides. Finally, we compare the mesophases of the G-quadruplexes, under PEG-induced crowding conditions, with the corresponding mesophases of the canonical duplex and triplex DNA analogues.
authors.affiliation: Department of Physics, University of Massachusetts, Amherst, MA 01003, United States.
authors.forename: Selcuk
authors.initials: S
authors.lastname: Yasar
authors.affiliation: Department of Macromolecular Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States.
authors.forename: Jacob B
authors.initials: JB
authors.lastname: Schimelman
authors.affiliation: Department of Physics, University of Massachusetts, Amherst, MA 01003, United States.
authors.forename: M Alphan
authors.initials: MA
authors.lastname: Aksoyoglu
authors.affiliation: Department of Macromolecular Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States.|Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States.|Department of Radiology, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States.|Department of Materials Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States.|Comprehensive Cancer Center, Division of General Medical Sciences and Oncology, Case Western Reserve University, 10900 Euclid Avenue,Cleveland, Ohio 44106, United States.
authors.forename: Nicole F
authors.initials: NF
authors.lastname: Steinmetz
authors.affiliation: Department of Macromolecular Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States.|Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States.|Department of Materials Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States.|Department of Physics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States.
authors.forename: Roger H
authors.initials: RH
authors.lastname: French
authors.affiliation: Department of Physics, University of Massachusetts, Amherst, MA 01003, United States.
authors.forename: V Adrian
authors.initials: VA
authors.lastname: Parsegian
authors.affiliation: Department of Physics, University of Massachusetts, Amherst, MA 01003, United States.|Department of Materials Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States.|Department of Theoretical Physics, J. Stefan Institute, SI-1000 Ljubljana, Slovenia.|Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Podgornik
mesh_terms: D001483:Base Sequence; D018360:Crystallography, X-Ray; D054856:G-Quadruplexes; D006801:Humans; D006860:Hydrogen Bonding; D008958:Models, Molecular; D016615:Telomere / Q000737:chemistry / Q000235:genetics / Q000648:ultrastructure*