title: Helically Assembled Pyrene Arrays on an RNA Duplex That Exhibit Circularly Polarized Luminescence with Excimer Formation.
abstract: Circularly polarized luminescence (CPL) was observed in pyrene zipper arrays helically arranged on an RNA duplex. Hybridization of complementary RNA strands having multiple (two to five) 2'-O-pyrenylmethyl modified nucleosides affords an RNA duplex with normal thermal stability. The pyrene fluorophores are assembled like a zipper in a well-defined helical manner along the axis of RNA duplex, which, upon 350 nm UV illumination, resulted in CPL emission with pyrene excimer formation. CPL (glum ) levels observed for the pyrene arrays in dilute aqueous solution were +2×10(-2) -+3.5×10(-2) , which are comparable with |glum | for chiral organic molecules and related systems. The positive CPL signals are consistent with a right-handed helical structure. Temperature dependence on CPL emission indicates that the stable rigid RNA structure is responsible for the strong CPL signals. The single pyrene-modified RNA duplex did not show any CPL signal.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo, 671-2280, Japan.
authors.forename: Mitsunobu
authors.initials: M
authors.lastname: Nakamura
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo, 671-2280, Japan.
authors.forename: Junpei
authors.initials: J
authors.lastname: Suzuki
authors.affiliation: Department of Polymer Chemistry, Kyoto University, Katsura, Kyoto, 615-8510, Japan.
authors.forename: Fuyuki
authors.initials: F
authors.lastname: Ota
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo, 671-2280, Japan.
authors.forename: Tadao
authors.initials: T
authors.lastname: Takada
authors.affiliation: Department of Polymer Chemistry, Kyoto University, Katsura, Kyoto, 615-8510, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Akagi
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo, 671-2280, Japan. yamana@eng.u-hyogo.ac.jp.
authors.forename: Kazushige
authors.initials: K
authors.lastname: Yamana
mesh_terms: D002942:Circular Dichroism; D005456:Fluorescent Dyes / Q000737:chemistry; D009690:Nucleic Acid Conformation; D011721:Pyrenes / Q000737:chemistry*; D012330:RNA, Double-Stranded / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D014466:Ultraviolet Rays
chemical_list: D005456:Fluorescent Dyes; D011721:Pyrenes; D012330:RNA, Double-Stranded
keywords: RNA duplexes; circularly polarized luminescence; excimers; helical structures; pyrene