title: Sulfonated Ni(II)porphyrin improves the detection of Z-DNA in condensed and non-condensed BZB DNA sequences.
abstract: We report a very selective and sensitive spectroscopic detection of Z-DNA embedded in B-DNA in condensed as well as non-condensed DNA using anionic Ni(II) meso-tetrakis(4-sulphonatophenyl)porphyrin, NiTPPS. A combination of micromolar concentrations of Ni(II) and spermine(4+) allowed us to prepare left-handed Z-DNA in short oligonucleotides without DNA condensation. A strong induced circular dichroism (ICD) signal was observed in the visible absorption region when NiTPPS was added to BZ DNA (Z-DNA fragment located at the end of a B-DNA tract with one B/Z DNA junction) and BZB DNA (Z-DNA sequence embedded in B-DNA having two B/Z DNA junctions). Almost no ICD signal was detected when NiTPPS was added to B-DNA. NiTPPS showed different binding modes with condensed and non-condensed Z-DNAs and allowed the distinction between condensed Z-DNA (positive bisignate CD couplet) and non-condensed Z-DNA (negative bisignate CD couplet).
authors.affiliation: Department of Chemistry, Doane College, 1014 Boswell Ave, Crete, NE 68333, USA.
authors.forename: Andrea E
authors.initials: AE
authors.lastname: Holmes
authors.forename: Jung Kyu
authors.initials: JK
authors.lastname: Choi
authors.forename: Jacob
authors.initials: J
authors.lastname: Francis
authors.forename: Alessandro
authors.initials: A
authors.lastname: D'Urso
authors.forename: Milan
authors.initials: M
authors.lastname: Balaz
mesh_terms: D002942:Circular Dichroism; D043542:DNA, Z-Form / Q000032:analysis / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013096:Spermine / Q000737:chemistry*
chemical_list: D043542:DNA, Z-Form; D011166:Porphyrins; D013096:Spermine; D009532:Nickel