title: Structure, folding and catalysis of the small nucleolytic ribozymes.
abstract: The small nucleolytic ribozymes are largely (but not exclusively) found in the RNA of plant pathogens and are involved in the self-catalysed processing of the concatameric RNA resulting from rolling circle replication. They catalyse a site-specific transesterification reaction in which their 2' hydroxyl attacks the 3' phosphate, with the exclusion of the 5' oxyanion. This requires an in-line geometry, which is not present in normal RNA structure. A significant part of the activation is probably provided by a distortion of the local conformation in order to facilitate the trajectory into the transition state and, thus, RNA folding and catalysis are intimately connected. A second element of the catalysis is provided by bound metal ions; however, a number of recent experiments cast doubt on the direct role of metal ions in the catalytic chemistry.
authors.affiliation: Cancer Research Campaign Nucleic Acid Structure Research Group, Department of Biochemistry, The University of Dundee, UK. dmjlilley@bad.dundee.ac.uk
authors.forename: D M
authors.initials: DM
authors.lastname: Lilley
mesh_terms: D002384:Catalysis; D003698:Hepatitis Delta Virus / Q000201:enzymology / Q000235:genetics; D019216:Metals, Heavy / Q000737:chemistry; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D016337:RNA, Catalytic / Q000737:chemistry*
chemical_list: D019216:Metals, Heavy; D016337:RNA, Catalytic