title: Probing a tRNA core that contributes to aminoacylation.
abstract: The contribution of the tRNA "core" to aminoacylation is beginning to be recognized. One example is the core region of Escherichia coli tRNA(Cys), which has been shown by biochemical studies to be important for aminoacylation. This core has several layers of unusual base-pairs, which are revealed by the recent crystal structure of the tRNA complexed with the elongation factor EF-Tu and an analog of GTP. One of these layers consists of a 9:[13:22] base-triple, rather than the 46:[13:22] or 45:[13:22] base-triple that is commonly observed in tRNA structure. Because 13:22 is an important element in aminoacylation of E. coli tRNA(Cys), a better understanding of its structure in the tRNA core will shed light on its role in aminoacylation. In this study, we used the phage T7 transcript of the tRNA as a substrate. We probed the structure of 13:22 by dimethyl sulfate and tested its partner in a base-triple by generating mutations that could be assayed for aminoacylation. The results of this study in general are in a better agreement with a 46:[13:22] base-triple that we previously proposed. Although these results are not interpreted as direct proof for the 46:[13:22] base-triple, they shed new light on features of the tRNA core that are important for aminoacylation.
authors.affiliation: Department of Biochemistry, Thomas Jefferson University, 233 South 10th Street, Philadelphia, BLSB 220, 19107, USA.
authors.forename: C S
authors.initials: CS
authors.lastname: Hamann
authors.forename: Y M
authors.initials: YM
authors.lastname: Hou
mesh_terms: D020029:Base Pairing; D001483:Base Sequence; D003545:Cysteine / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009690:Nucleic Acid Conformation; D012329:RNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D012331:RNA, Fungal / Q000737:chemistry; D012350:RNA, Transfer, Cys / Q000737:chemistry* / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D013463:Sulfuric Acid Esters; D014158:Transcription, Genetic
chemical_list: D012329:RNA, Bacterial; D012331:RNA, Fungal; D012350:RNA, Transfer, Cys; D013463:Sulfuric Acid Esters; C007482:dimethyl sulfate; D003545:Cysteine