3twm | pdb_00003twm
Crystal structure of Arabidopsis thaliana FPG
Structural highlights
Function[FPG_ARATH] Involved in base excision repair of DNA damaged by oxidation or by mutagenic agents. Acts as DNA glycosylase that recognizes and removes damaged bases. Can process efficiently 4,6-diamino-5-formamidopyrimidine (FapyA), 2,6-diamino-4- hydroxy-5-formamidopyrimidine (FapyG) and the further oxidation products of 8-oxoguanine (8-oxoG), such as guanidinohydantoin and spiroiminodihydantoin. Has marginal activity towards 8-oxoG. Has AP (apurinic/apyrimidinic) lyase activity. Cleaves the DNA backbone by beta-delta elimination to generate a single-strand break at the site of the removed base with both 3'- and 5'-phosphates.[1] [2] [3] Publication Abstract from PubMedFormamidopyrimidine-DNA glycosylase (Fpg; MutM) is a DNA repair enzyme widely distributed in bacteria. Fpg recognizes and excises oxidatively modified purines, 4,6-diamino-5-formamidopyrimidine, 2,6-diamino-4-hydroxy-5-formamidopyrimidine and 8-oxoguanine (8-oxoG), with similar excision kinetics. It exhibits some lesser activity toward 8-oxoadenine. Fpg enzymes are also present in some plant and fungal species. The eukaryotic Fpg homologs exhibit little or no activity on DNA containing 8-oxoG, but they recognize and process its oxidation products, guanidinohydantoin (Gh) and spiroiminohydantoin (Sp). To date, several structures of bacterial Fpg enzymes unliganded or in complex with DNA containing a damaged base have been published but there is no structure of a eukaryotic Fpg. Here we describe the first crystal structure of a plant Fpg, Arabidopsis thaliana (AthFpg), unliganded and bound to DNA containing an abasic site analog, tetrahydrofuran (THF). Although AthFpg shares a common architecture with other Fpg glycosylases, it harbors a zincless finger, previously described in a subset of Nei enzymes, such as human NEIL1 and Mimivirus Nei1. Importantly the "alphaF-beta9/10 loop" capping 8-oxoG in the active site of bacterial Fpg is very short in AthFpg. Deletion of a segment encompassing residues 213-229 in Escherichia coli Fpg (EcoFpg) and corresponding to the "alphaF-beta9/10 loop" does not affect the recognition and removal of oxidatively damaged DNA base lesions, with the exception of 8-oxoG. Although the exact role of the loop remains to be further explored, it is now clear that this protein segment is specific to the processing of 8-oxoG. Structural and biochemical studies of a plant formamidopyrimidine-DNA glycosylase reveal why eukaryotic Fpg glycosylases do not excise 8-oxoguanine.,Duclos S, Aller P, Jaruga P, Dizdaroglu M, Wallace SS, Doublie S DNA Repair (Amst). 2012 Jul 10. PMID:22789755[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
| ||||||||||||||||||||||||
