4unf | pdb_00004unf

Crystal structure of Deinococcus radiodurans Endonuclease III-1

spinqualitylabelsall models 4unf, resolution 2.15Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4unf is a 1 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ACT, MG, SF4 Related: 4uob Activity: DNA-(apurinic or apyrimidinic site) lyase, with EC number 4.2.99.18 Resources: FirstGlance, OCA, RCSB, PDBsum Function [Q9RRQ0_DEIRA] DNA repair enzyme that has both DNA N-glycosylase activity and AP-lyase activity.[PIRNR:PIRNR001435] Publication Abstract from PubMed While most bacteria possess a single gene encoding the bifunctional DNA glycosylase Endonuclease III (EndoIII) in their genomes, Deinococcus radiodurans possesses three: DR2438 (DrEndoIII1), DR0289 (DrEndoIII2) and DR0982 (DrEndoIII3). Here we have determined the crystal structures of DrEndoIII1 and an N-terminally truncated form of DrEndoIII3 (DrEndoIII3Delta76). We have also generated a homology model of DrEndoIII2 and measured activity of the three enzymes. All three structures consist of two all alpha-helical domains, one of which exhibits a [4Fe-4S] cluster and the other a HhH-motif, separated by a DNA binding cleft, similar to previously determined structures of endonuclease III from Escherichia coli and Geobacillus stearothermophilus. However, both DrEndoIII1 and DrEndoIII3 possess an extended HhH motif with extra helical features and an altered electrostatic surface potential. In addition, the DNA binding cleft of DrEndoIII3 seems to be less accessible for DNA interactions, while in DrEndoIII1 it seems to be more open. Analysis of the enzyme activities shows that DrEndoIII2 is most similar to the previously studied enzymes, while DrEndoIII1 seems to be more distant with a weaker activity towards substrate DNA containing either thymine glycol or an abasic site. DrEndoIII3 is the most distantly related enzyme and displays no detectable activity towards these substrates even though the suggested catalytic residues are conserved. Based on a comparative structural analysis, we suggest that the altered surface potential, shape of the substrate-binding pockets and specific amino acid substitutions close to the active site and in the DNA interacting loops may underlie the unexpected differences in activity. Structural and functional characterization of two unusual endonuclease III enzymes from Deinococcus radiodurans.,Sarre A, Okvist M, Klar T, Hall DR, Smalas AO, McSweeney S, Timmins J, Moe E J Struct Biol. 2015 Jul 11. pii: S1047-8477(15)00138-0. doi:, 10.1016/j.jsb.2015.05.009. PMID:26172070 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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