title: 4-Aminobenzimidazole-1-methylthymine: a model for investigating Hoogsteen base-pairing between adenine and thymine.
abstract: We report the infrared spectrum of the 4-aminobenzimidazole-1-methylthymine (4ABI:1MT) heterodimer, detected by femtosecond multiphoton ionization. Based on calculations of both the harmonic and the anharmonic frequencies, the observed vibrational spectrum is assigned to a structure that mimics the Hoogsteen base pairing of adenine and thymine. A notable observation made in the course of this study is that there is a significant imbalance in the observed strengths of the H-bonds. While the N···H-N bond reveals a large red shift of >700 cm(-1) for the NH stretch frequency, the N-H···O bond is characterized by only a 50 cm(-1) shift. The importance of this observation in the formation of Hoogsteen duplexes by thymine-based oligonucleotides is discussed.
authors: Institut für Physikalische und Theoretische Chemie, Goethe-Universität, Frankfurt/Main, Germany.
authors: Yevgeniy
authors: Y
authors: Nosenko
authors: Maksim
authors: M
authors: Kunitski
authors: Tina
authors: T
authors: Stark
authors: Michael
authors: M
authors: Göbel
authors: Pilarisetty
authors: P
authors: Tarakeshwar
authors: Bernhard
authors: B
authors: Brutschy
mesh_terms: D000225:Adenine / Q000737:chemistry*; D020029:Base Pairing; D008956:Models, Chemical; D013941:Thymine / Q000031:analogs & derivatives* / Q000737:chemistry*
chemical_list: C569910:4-aminobenzimidazole-1-methylthymine; D000225:Adenine; D013941:Thymine