title: 5-Hydroxy-5-methylhydantoin DNA lesion, a molecular trap for DNA glycosylases.
abstract: DNA base-damage recognition in the base excision repair (BER) is a process operating on a wide variety of alkylated, oxidized and degraded bases. DNA glycosylases are the key enzymes which initiate the BER pathway by recognizing and excising the base damages guiding the damaged DNA through repair synthesis. We report here biochemical and structural evidence for the irreversible entrapment of DNA glycosylases by 5-hydroxy-5-methylhydantoin, an oxidized thymine lesion. The first crystal structure of a suicide complex between DNA glycosylase and unrepaired DNA has been solved. In this structure, the formamidopyrimidine-(Fapy) DNA glycosylase from Lactococcus lactis (LlFpg/LlMutM) is covalently bound to the hydantoin carbanucleoside-containing DNA. Coupling a structural approach by solving also the crystal structure of the non-covalent complex with site directed mutagenesis, this atypical suicide reaction mechanism was elucidated. It results from the nucleophilic attack of the catalytic N-terminal proline of LlFpg on the C5-carbon of the base moiety of the hydantoin lesion. The biological significance of this finding is discussed.
authors.affiliation: Centre de Biophysique Moléculaire, UPR4301, CNRS, rue Charles Sadron, 45071 Orléans cedex 02, France.
authors.forename: Yann-Vaï
authors.initials: YV
authors.lastname: Le Bihan
authors.forename: Maria
authors.initials: M
authors.lastname: Angeles Izquierdo
authors.forename: Franck
authors.initials: F
authors.lastname: Coste
authors.forename: Pierre
authors.initials: P
authors.lastname: Aller
authors.forename: Françoise
authors.initials: F
authors.lastname: Culard
authors.forename: Tim H
authors.initials: TH
authors.lastname: Gehrke
authors.forename: Kadija
authors.initials: K
authors.lastname: Essalhi
authors.forename: Thomas
authors.initials: T
authors.lastname: Carell
authors.forename: Bertrand
authors.initials: B
authors.lastname: Castaing
mesh_terms: D020134:Catalytic Domain; D004247:DNA / Q000737:chemistry*; D004249:DNA Damage; D043382:DNA-Formamidopyrimidine Glycosylase / Q000737:chemistry*; D006827:Hydantoins / Q000737:chemistry*; D008958:Models, Molecular; D011485:Protein Binding
chemical_list: C561769:5-hydroxy-5-methylhydantoin; D006827:Hydantoins; D004247:DNA; D043382:DNA-Formamidopyrimidine Glycosylase