title: Adenine-aptamer complexes: a bipartite RNA site that binds the adenine nucleic base.
abstract: RNA aptamers that are able to complex free adenine have been isolated by a SELEX (systematic evolution of ligands by exponential enrichment) procedure. The adenine binding site was revealed by sequence alignment for a prevalent cluster of aptamers, and its structure and interactions with adenine were probed by RNase digestion studies, lead cleavage, boundary determination experiments, and truncated sequences studies. A new purine binding motif was functionally and structurally characterized and compared with other RNAs specific to purine or adenylated compounds. The affinity for adenine and the specificity for other related targets were quantified. This work suggests that the adenine binding site is composed of two independent secondary structure elements forming a bipartite binding site that interacts with adenine in a new mode of purine recognition. Such binding is of great interest because the imidazole moiety is not trapped in the binding site, and would easily be available for catalytic activity.
authors.affiliation: Institut Jacques Monod, Laboratoire de Biochimie de l'Evolution et Adaptabilité Moléculaire, Tour 43, 2 place Jussieu, 75251 Paris Cedex 05, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Meli
authors.forename: Jacques
authors.initials: J
authors.lastname: Vergne
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Décout
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Maurel
mesh_terms: D000225:Adenine / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D002384:Catalysis; D003001:Cloning, Molecular; D017931:DNA Primers; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000378:metabolism*; D012313:RNA / Q000378:metabolism*; D012689:Sequence Homology, Nucleic Acid; D012996:Solutions
chemical_list: D017931:DNA Primers; D009838:Oligodeoxyribonucleotides; D012996:Solutions; D012313:RNA; D000225:Adenine