2ssp
LEUCINE-272-ALANINE URACIL-DNA GLYCOSYLASE BOUND TO ABASIC SITE-CONTAINING DNA
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| , resolution 2.25Å | |||||||
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| Ligands: | , , , , | ||||||
| Activity: | Uridine nucleosidase, with EC number 3.2.2.3 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
OverviewOverview
Three high-resolution crystal structures of DNA complexes with wild-type and mutant human uracil-DNA glycosylase (UDG), coupled kinetic characterizations and comparisons with the refined unbound UDG structure help resolve fundamental issues in the initiation of DNA base excision repair (BER): damage detection, nucleotide flipping versus extrahelical nucleotide capture, avoidance of apurinic/apyrimidinic (AP) site toxicity and coupling of damage-specific and damage-general BER steps. Structural and kinetic results suggest that UDG binds, kinks and compresses the DNA backbone with a 'Ser-Pro pinch' and scans the minor groove for damage. Concerted shifts in UDG simultaneously form the catalytically competent active site and induce further compression and kinking of the double-stranded DNA backbone only at uracil and AP sites, where these nucleotides can flip at the phosphate-sugar junction into a complementary specificity pocket. Unexpectedly, UDG binds to AP sites more tightly and more rapidly than to uracil-containing DNA, and thus may protect cells sterically from AP site toxicity. Furthermore, AP-endonuclease, which catalyzes the first damage-general step of BER, enhances UDG activity, most likely by inducing UDG release via shared minor groove contacts and flipped AP site binding. Thus, AP site binding may couple damage-specific and damage-general steps of BER without requiring direct protein-protein interactions.
About this StructureAbout this Structure
2SSP is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Base excision repair initiation revealed by crystal structures and binding kinetics of human uracil-DNA glycosylase with DNA., Parikh SS, Mol CD, Slupphaug G, Bharati S, Krokan HE, Tainer JA, EMBO J. 1998 Sep 1;17(17):5214-26. PMID:9724657
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