title: A DNA metalloenzyme with DNA ligase activity.
abstract: Single-stranded DNA can fold into well-defined sequence-dependent tertiary structures that specifically bind a variety of target molecules, raising the possibility that some folded single-stranded DNAs might exhibit catalytic activities similar to those of ribozymes and protein enzymes. Derivatives of the hammerhead ribozyme that contain a majority of deoxyribonucleotides retain the ability to cleave RNA, and a 'deoxyribozyme' was generated by leaving all essential ribonucleotides of the hammerhead on the RNA 'substrate'. Recently in vitro selection has been used to isolate a DNA sequence that shows Pb(2+)-dependent RNA-cleaving activity. Here we report the isolation by in vitro selection of a small single-stranded DNA that is a Zn2+/Cu(2+)-dependent metalloenzyme. The enzyme catalyses the formation of a new phosphodiester bond by the condensation of the 5'-hydroxyl of one oligodeoxynucleotide and a 3'-phosphorimidazolide on another oligodeoxynucleotide, and shows multiple turnover ligation.
authors.affiliation: Department of Genetics, Harvard Medical School, Massachusetts General Hospital, Boston 02114, USA.
authors.forename: B
authors.initials: B
authors.lastname: Cuenoud
authors.forename: J W
authors.initials: JW
authors.lastname: Szostak
mesh_terms: D001483:Base Sequence; D002384:Catalysis; D004247:DNA / Q000378:metabolism*; D011088:DNA Ligases / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000378:metabolism*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation
chemical_list: D004277:DNA, Single-Stranded; D008670:Metals; D004247:DNA; D011088:DNA Ligases