1UUG

ESCHERICHIA COLI URACIL-DNA GLYCOSYLASE:INHIBITOR COMPLEX WITH WILD-TYPE UDG AND WILD-TYPE UGI

1UUG の概要

• エントリーDOI: 10.2210/pdb1uug/pdb
• 分子名称: URACIL-DNA GLYCOSYLASE, URACIL-DNA GLYCOSYLASE INHIBITOR (3 entities in total)
• 機能のキーワード: dna base excision repair, protein mimicry of dna, protein inhibitor, replication, hydrolase
• 由来する生物種: Escherichia coli K12; 詳細
• 細胞内の位置: Cytoplasm: P12295
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 70415.71

構造登録者

Mol, C.D.,Arvai, A.S.,Putnam, C.D.,Tainer, J.A. (登録日: 1998-10-31, 公開日: 1999-03-25, 最終更新日: 2024-04-03)

主引用文献

Putnam, C.D.,Shroyer, M.J.,Lundquist, A.J.,Mol, C.D.,Arvai, A.S.,Mosbaugh, D.W.,Tainer, J.A.
Protein mimicry of DNA from crystal structures of the uracil-DNA glycosylase inhibitor protein and its complex with Escherichia coli uracil-DNA glycosylase
J.Mol.Biol., 287:331-346, 1999

PubMed Abstract: Uracil-DNA glycosylase (UDG), which is a critical enzyme in DNA base-excision repair that recognizes and removes uracil from DNA, is specifically and irreversably inhibited by the thermostable uracil-DNA glycosylase inhibitor protein (Ugi). A paradox for the highly specific Ugi inhibition of UDG is how Ugi can successfully mimic DNA backbone interactions for UDG without resulting in significant cross-reactivity with numerous other enzymes that possess DNA backbone binding affinity. High-resolution X-ray crystal structures of Ugi both free and in complex with wild-type and the functionally defective His187Asp mutant Escherichia coli UDGs reveal the detailed molecular basis for duplex DNA backbone mimicry by Ugi. The overall shape and charge distribution of Ugi most closely resembles a midpoint in a trajectory between B-form DNA and the kinked DNA observed in UDG:DNA product complexes. Thus, Ugi targets the mechanism of uracil flipping by UDG and appears to be a transition-state mimic for UDG-flipping of uracil nucleotides from DNA. Essentially all the exquisite shape, electrostatic and hydrophobic complementarity for the high-affinity UDG-Ugi interaction is pre-existing, except for a key flip of the Ugi Gln19 carbonyl group and Glu20 side-chain, which is triggered by the formation of the complex. Conformational changes between unbound Ugi and Ugi complexed with UDG involve the beta-zipper structural motif, which we have named for the reversible pairing observed between intramolecular beta-strands. A similar beta-zipper is observed in the conversion between the open and closed forms of UDG. The combination of extremely high levels of pre-existing structural complementarity to DNA binding features specific to UDG with key local conformational changes in Ugi resolves the UDG-Ugi paradox and suggests a potentially general structural solution to the formation of very high affinity DNA enzyme-inhibitor complexes that avoid cross- reactivity.

PubMed: 10080896
DOI: 10.1006/jmbi.1999.2605

実験手法

X-RAY DIFFRACTION (2.4 Å)