3g91 | pdb_00003g91

1.2 Angstrom structure of the exonuclease III homologue Mth0212

spinqualitylabelsall models 3g91, resolution 1.23Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3g91 is a 1 chain structure with sequence from Methanothermobacter thermautotrophicus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GOL, MG, PEG, PG4, PO4 Related: 3fzi, 3g00, 3g0a, 3g0r, 3g1k, 3g2c, 3g2d, 3g38, 3g3c, 3g3y, 3g4t, 3g8v, 3ga6 Gene: mth0212, MTH212, MTH_212 (Methanothermobacter thermautotrophicus) Activity: Exodeoxyribonuclease III, with EC number 3.1.11.2 Resources: FirstGlance, OCA, RCSB, PDBsum Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The reliable repair of pre-mutagenic U/G mismatches that originated from hydrolytic cytosine deamination is crucial for the maintenance of the correct genomic information. In most organisms, any uracil base in DNA is attacked by uracil DNA glycosylases (UDGs), but at least in Methanothermobacter thermautotrophicus DeltaH, an alternative strategy has evolved. The exonuclease III homologue Mth212 from the thermophilic archaeon M. thermautotrophicus DeltaH exhibits a DNA uridine endonuclease activity in addition to the apyrimidinic/apurinic site endonuclease and 3'-->5'exonuclease functions. Mth212 alone compensates for the lack of a UDG in a single-step reaction thus substituting the two-step pathway that requires the consecutive action of UDG and apyrimidinic/apurinic site endonuclease. In order to gain deeper insight into the structural basis required for the specific uridine recognition by Mth212, we have characterized the enzyme by means of X-ray crystallography. Structures of Mth212 wild-type or mutant proteins either alone or in complex with DNA substrates and products have been determined to a resolution of up to 1.2 A, suggesting key residues for the uridine endonuclease activity. The insertion of the side chain of Arg209 into the DNA helical base stack resembles interactions observed in human UDG and seems to be crucial for the uridine recognition. In addition, Ser171, Asn153, and Lys125 in the substrate binding pocket appear to have important functions in the discrimination of aberrant uridine against naturally occurring thymidine and cytosine residues in double-stranded DNA. Crystal structure analysis of DNA uridine endonuclease Mth212 bound to DNA.,Lakomek K, Dickmanns A, Ciirdaeva E, Schomacher L, Ficner R J Mol Biol. 2010 Jun 18;399(4):604-17. Epub 2010 Apr 29. PMID:20434457 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Exonuclease

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