title: Crystal structure of Ce(IV)/dipicolinate complex as catalyst for DNA hydrolysis.
abstract: The structures of Ce(4+) complexes that are active for DNA hydrolysis were determined for the first time by X-ray crystallography. The crystals were prepared from a 1:2 mixture of Ce(NH(4))(2)(NO(3))(6) and dipicolinic acid (2,6-pyridinedicarboxylic acid). Depending on the recrystallization conditions, three types of crystals were obtained. Some of the Ce(4+) ions in these complexes have enough coordinated water molecules that can directly and indirectly participate in the catalysis. The distances between the Ce(4+) and the dipicolinate ligand are considerably shorter than those in the corresponding La(3+) and Ce(3+) complexes. On the other hand, the distances between the Ce(4+) and its coordinated water are similar to those for the La(3+) and Ce(3+) complexes. In a proposed mechanism of DNA hydrolysis, the scissile phosphodiester linkage is notably activated by coordination to Ce(4+) and attacked by the Ce(4+)-bound hydroxide. The process is further assisted by acid catalysis of Ce(4+)-bound water.
authors.affiliation: The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Katada
authors.forename: Hidetake
authors.initials: H
authors.lastname: Seino
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Mizobe
authors.forename: Jun
authors.initials: J
authors.lastname: Sumaoka
authors.forename: Makoto
authors.initials: M
authors.lastname: Komiyama
mesh_terms: D001483:Base Sequence; D002384:Catalysis; D002563:Cerium / Q000737:chemistry* / Q000494:pharmacology*; D018360:Crystallography, X-Ray; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D006868:Hydrolysis / Q000187:drug effects; D007700:Kinetics; D008024:Ligands; D009596:Nitrophenols / Q000737:chemistry; D009841:Oligonucleotides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010848:Picolinic Acids / Q000737:chemistry* / Q000494:pharmacology*; D011725:Pyridines / Q000737:chemistry / Q000494:pharmacology; D014867:Water / Q000737:chemistry
chemical_list: D008024:Ligands; D009596:Nitrophenols; D009841:Oligonucleotides; D010848:Picolinic Acids; D011725:Pyridines; D014867:Water; D002563:Cerium; C002887:bis(4-nitrophenyl)phosphate; D004247:DNA; C023666:pyridine; C030614:picolinic acid