title: Fluorescent properties of an unnatural nucleobase, 2-amino-6-(2-thienyl)purine, in DNA and RNA fragments.
abstract: Nucleoside derivatives of 2-amino-6-(2-thienyl)purine (s) are fluorescent and can be site-specifically incorporated into RNA by transcription mediated by unnatural base pairs between s and its complementary bases. To utilize the fluorescent s base as a probe, we examined the fluorescent properties of s in DNA and RNA fragments. The nucleoside of s exhibited a fluorescence emission centered at 432 nm, characterized by two major excitation maxima (299 and 352 nm), and its quantum yield was 0.41 at pH 7.0. The fluorescence intensity of s in DNA fragments (12-mer) differed depending on circumstances such as the base components, stacking, and pairings. The s base was introduced into a tRNA at specific positions by specific transcription using the unnatural base pairs. The fluorescence intensity of s at each position reflected the local structural features of the tRNA molecules.
authors.affiliation: Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan.
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Mitsui
authors.forename: Michiko
authors.initials: M
authors.lastname: Kimoto
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Yokoyama
authors.forename: Ichiro
authors.initials: I
authors.lastname: Hirao
mesh_terms: D020029:Base Pairing; D004247:DNA / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D015341:Nucleic Acid Probes / Q000737:chemistry*; D011687:Purines / Q000737:chemistry*; D012343:RNA, Transfer / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: C435686:2-amino-6-(2-thienyl)purine; D005456:Fluorescent Dyes; D015341:Nucleic Acid Probes; D011687:Purines; D004247:DNA; D012343:RNA, Transfer