title: Thermodynamic characterization of the Saccharomyces cerevisiae telomerase RNA pseudoknot domain in vitro.
abstract: Recent structural and functional characterization of the pseudoknot in the Saccharomyces cerevisiae telomerase RNA (TLC1) has demonstrated that tertiary structure is present, similar to that previously described for the human and Kluyveromyces lactis telomerase RNAs. In order to biophysically characterize the identified pseudoknot secondary and tertiary structures, UV-monitored thermal denaturation experiments, nuclear magnetic resonance spectroscopy, and native gel electrophoresis were used to investigate various potential conformations in the pseudoknot domain in vitro, in the absence of the telomerase protein. Here, we demonstrate that alternative secondary structures are not mutually exclusive in the S. cerevisiae telomerase RNA, tertiary structure contributes 1.5 kcal mol(-1) to the stability of the pseudoknot (≈ half the stability observed for the human telomerase pseudoknot), and identify additional base pairs in the 3' pseudoknot stem near the helical junction. In addition, sequence conservation in an adjacent overlapping hairpin appears to prevent dimerization and alternative conformations in the context of the entire pseudoknot-containing region. Thus, this work provides a detailed in vitro characterization of the thermodynamic features of the S. cerevisiae TLC1 pseudoknot region for comparison with other telomerase RNA pseudoknots.
authors.affiliation: Department of Chemistry, State University of New York at Albany, Albany, New York 12222, USA.
authors.forename: Fei
authors.initials: F
authors.lastname: Liu
authors.forename: Yoora
authors.initials: Y
authors.lastname: Kim
authors.forename: Charmion
authors.initials: C
authors.lastname: Cruickshank
authors.forename: Carla A
authors.initials: CA
authors.lastname: Theimer
mesh_terms: D020029:Base Pairing; D001483:Base Sequence; D019281:Dimerization; D055029:Inverted Repeat Sequences; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012313:RNA / Q000737:chemistry* / Q000378:metabolism*; D020871:RNA Stability; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D012965:Sodium Chloride / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D019098:Telomerase / Q000737:chemistry* / Q000378:metabolism*; D013816:Thermodynamics; D044366:Transition Temperature
chemical_list: D012996:Solutions; C422952:telomerase RNA; D012965:Sodium Chloride; D012313:RNA; D019098:Telomerase