title: The first derivative of a function of circular dichroism spectra: biophysical study of human telomeric G-quadruplex.
abstract: Depending on conditions and base modifications, telomeric repeats can form many topological structures; parallel, antiparallel and hybrid forms. The influence of salts and some specific ligands on conformational changes has already been established. In this study, we analyze the human telomeric repeats 5'-GGG(TTAGGG)(3)-3' because this sequence forms topologically different structures under various conditions which have been well described by many authors. CD results are compared with electrophoretic and UV absorption spectroscopy results obtained under corresponding conditions in the presence of different ratios of sodium and potassium ions and polyethylene glycol (PEG). We confirmed that the most stable G-quadruplexes could only form under crowding conditions with PEG-200 and K(+) ion, but the molecularity is increased. Other monovalent ions without the presence of K(+) are unable to form the parallel quadruplex conformer and no change of stoichiometry is observed, even when PEG-200 is present. The first derivative of a function applied to CD spectra seems to be a powerful tool for spectra evaluation of any G-quadruplex, and could be more unambiguous than a direct analysis of original spectra.
authors.affiliation: Department of Biochemistry, Institute of Chemistry, Faculty of Sciences, P. J. Safarik University, 04001, Košice, Slovakia. viktor.viglasky@upjs.sk
authors.forename: Viktor
authors.initials: V
authors.lastname: Víglaský
authors.forename: Katarína
authors.initials: K
authors.lastname: Tlučková
authors.forename: Luboš
authors.initials: L
authors.lastname: Bauer
mesh_terms: D002412:Cations / Q000737:chemistry; D002942:Circular Dichroism / Q000379:methods*; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D054856:G-Quadruplexes; D006801:Humans; D011092:Polyethylene Glycols / Q000737:chemistry; D011188:Potassium / Q000737:chemistry; D012964:Sodium / Q000737:chemistry; D012996:Solutions; D016615:Telomere / Q000737:chemistry*
chemical_list: D002412:Cations; D012996:Solutions; D011092:Polyethylene Glycols; D012964:Sodium; D011188:Potassium
references.citation: Chirality. 2008 Mar;20(3-4):431-40
references.pmid: 17853398
references.citation: J Am Chem Soc. 2009 Apr 1;131(12):4301-9
references.pmid: 19271707
references.citation: Biopolymers. 2007 Sep;87(1):74-84
references.pmid: 17549693
references.citation: J Am Chem Soc. 2006 Aug 2;128(30):9963-70
references.pmid: 16866556
references.citation: Nature. 2002 Jun 20;417(6891):876-80
references.pmid: 12050675
references.citation: Biochemistry. 2007 Apr 17;46(15):4654-60
references.pmid: 17381076
references.citation: Biochemistry. 2010 Mar 16;49(10):2110-20
references.pmid: 20143878
references.citation: Biochem Biophys Res Commun. 2007 Jan 19;352(3):812-7
references.pmid: 17150180
references.citation: Nucleic Acids Res. 2007;35(11):3646-53
references.pmid: 17488850
references.citation: Spectrochim Acta A Mol Biomol Spectrosc. 2006 Jul;64(4):835-43
references.pmid: 16490387
references.citation: Nucleic Acids Res. 2006 May 19;34(9):2723-35
references.pmid: 16714449
references.citation: Nucleic Acids Res. 2007;35(19):6517-25
references.pmid: 17895279
references.citation: Nucleic Acids Res. 2005 Oct 12;33(18):5851-60
references.pmid: 16221978
references.citation: Structure. 1993 Dec 15;1(4):263-82
references.pmid: 8081740
references.citation: J Am Chem Soc. 2002 Dec 4;124(48):14286-7
references.pmid: 12452685
references.citation: Nucleic Acids Res. 2008 Oct;36(17):5482-515
references.pmid: 18718931
references.citation: Biochemistry. 2007 Mar 20;46(11):3036-44
references.pmid: 17311417
references.citation: Biochemistry. 2002 Dec 17;41(50):15017-24
references.pmid: 12475251
references.citation: Nucleic Acids Res. 2005 Aug 16;33(14):4649-59
references.pmid: 16106044
references.citation: Nucleic Acids Res. 2009 Oct;37(19):6625-34
references.pmid: 19717545
references.citation: Nucleic Acids Res. 2009 Apr;37(6):1713-25
references.pmid: 19190094
references.citation: J Phys Chem B. 2009 Mar 5;113(9):2676-83
references.pmid: 19708205
references.citation: Biophys Chem. 2008 Aug;136(2-3):124-7
references.pmid: 18562078
references.citation: Nat Protoc. 2007;2(11):2649-54
references.pmid: 18007600
references.citation: FEBS J. 2010 Mar;277(5):1098-106
references.pmid: 19951355
references.citation: FEBS Lett. 1998 Sep 11;435(1):74-8
references.pmid: 9755862
references.citation: Nucleic Acids Res. 2003 Feb 15;31(4):1156-63
references.pmid: 12582234
references.citation: Anal Bioanal Chem. 2003 Apr;375(8):1006-10
references.pmid: 12733011