title: Crystal structure of an RNA polymerase ribozyme in complex with an antibody fragment.
abstract: All models of the RNA world era invoke the presence of ribozymes that can catalyse RNA polymerization. The class I ligase ribozyme selected in vitro 15 years ago from a pool of random RNA sequences catalyses formation of a 3',5'-phosphodiester linkage analogous to a single step of RNA polymerization. Recently, the three-dimensional structure of the ligase was solved in complex with U1A RNA-binding protein and independently in complex with an antibody fragment. The RNA adopts a tripod arrangement and appears to use a two-metal ion mechanism similar to protein polymerases. Here, we discuss structural implications for engineering a true polymerase ribozyme and describe the use of the antibody framework both as a portable chaperone for crystallization of other RNAs and as a platform for exploring steps in evolution from the RNA world to the RNA-protein world.
authors.affiliation: Department of Biochemistry and Molecular Biology, The University of Chicago, Gordon Center for Integrative Science, Room W406, Chicago, IL 60637, USA. jpicciri@uchicago.edu
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Piccirilli
authors.forename: Yelena
authors.initials: Y
authors.lastname: Koldobskaya
mesh_terms: D017151:Antibodies, Catalytic / Q000737:chemistry*; D002384:Catalysis; D020134:Catalytic Domain; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry*; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D019151:Peptide Library; D011118:Polynucleotide Ligases / Q000737:chemistry; D016337:RNA, Catalytic / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry; D012261:Ribonucleoproteins / Q000737:chemistry; D012265:Ribonucleotides / Q000737:chemistry*
chemical_list: D017151:Antibodies, Catalytic; D007140:Immunoglobulin Fab Fragments; D019151:Peptide Library; D016337:RNA, Catalytic; D011994:Recombinant Proteins; D012261:Ribonucleoproteins; D012265:Ribonucleotides; D012321:DNA-Directed RNA Polymerases; D011118:Polynucleotide Ligases