24uu

Crystal structure of Endonuclease IV from Chlamydophila pneumoniae

spinqualitylabelsall models 24uu, resolution 1.97Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 24uu is a 2 chain structure with sequence from Chlamydia pneumoniae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.97Å Ligands: ACT, EDO, FMT, MG, MLI, PEG, PPI, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function END4_CHLPN Endonuclease IV plays a role in DNA repair. It cleaves phosphodiester bonds at apurinic or apyrimidinic (AP) sites, generating a 3'-hydroxyl group and a 5'-terminal sugar phosphate. Publication Abstract from PubMed DNA damage requires repair via the endonuclease IV-mediated base excision repair (BER) pathway, which corrects apurinic/apyrimidinic (AP) sites. Chlamydophila pneumoniae AP endonuclease IV (CpEndoIV), the sole AP endonuclease in this pathogen, is crucial for genomic integrity. As humans lack a homologous protein, it represents a potential therapeutic target. In this study, we report the first crystal structure of CpEndoIV at 1.97 A resolution. The structure reveals two Zn(2+), one Mg(2+), and a malonate molecule bound in the active site, marking the first observation of Mg(2+) coordination in the EndoIV family. Compared to the three-Zn(2+) model with a narrow, deep pocket for precise AP-site cleavage, the Zn(2+)/Mg(2+)-bound state has a wider, shallower pocket that might promote diverse catalytic activities. Combined with enzymatic assays, we suggest that the mixed Zn(2+)/Mg(2+) model is better adapted for CpEndoIV to operate under host oxidative stress. Malonate binds to the metal ions, occupying the positions normally coordinated by water molecules. This binding mode may mimic the coordination of the substrate to the metal ions, and the protein conformation resembles that of the enzyme upon substrate binding at the active site. This study provides a structural basis for the functional characterization of CpEndoIV and offers a reference for the development of targeted inhibitors against diseases caused by Chlamydophila pneumoniae. Crystal Structure and Activity Analysis of Chlamydophila pneumoniae AP Endonuclease IV.,Jin J, Zhang Y, Guo S, Yang L, Liu H, Liu L, Gao W Biomolecules. 2026 Apr 17;16(4):594. doi: 10.3390/biom16040594. PMID:42072715 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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