3jr4

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MutM interrogating an extrahelical G

Structural highlights

3jr4 is a 3 chain structure with sequence from Geobacillus stearothermophilus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.601Å
Ligands:	,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

P84131_GEOSE Involved in base excision repair of DNA damaged by oxidation or by mutagenic agents. Acts as DNA glycosylase that recognizes and removes damaged bases. Has a preference for oxidized purines, such as 7,8-dihydro-8-oxoguanine (8-oxoG). Has AP (apurinic/apyrimidinic) lyase activity and introduces nicks in the DNA strand. Cleaves the DNA backbone by beta-delta elimination to generate a single-strand break at the site of the removed base with both 3'- and 5'-phosphates (By similarity).[HAMAP-Rule:MF_00103][SAAS:SAAS020629_004_120556]

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

MutM, a bacterial DNA glycosylase, protects genome integrity by catalyzing glycosidic bond cleavage of 8-oxoguanine (oxoG) lesions, thereby initiating base excision DNA repair. The process of searching for and locating oxoG lesions is especially challenging, because of the close structural resemblance of oxoG to its million-fold more abundant progenitor, G. Extrusion of the target nucleobase from the DNA double helix to an extrahelical position is an essential step in lesion recognition and catalysis by MutM. Although the interactions between the extruded oxoG and the active site of MutM have been well characterized, little is known in structural detail regarding the interrogation of extruded normal DNA bases by MutM. Here we report the capture and structural elucidation of a complex in which MutM is attempting to present an undamaged G to its active site. The structure of this MutM-extrahelical G complex provides insights into the mechanism MutM employs to discriminate against extrahelical normal DNA bases and into the base extrusion process in general.

Entrapment and structure of an extrahelical guanine attempting to enter the active site of a bacterial DNA glycosylase, MutM.,Qi Y, Spong MC, Nam K, Karplus M, Verdine GL J Biol Chem. 2010 Jan 8;285(2):1468-78. Epub 2009 Nov 4. PMID:19889642^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Qi Y, Spong MC, Nam K, Karplus M, Verdine GL. Entrapment and structure of an extrahelical guanine attempting to enter the active site of a bacterial DNA glycosylase, MutM. J Biol Chem. 2010 Jan 8;285(2):1468-78. Epub 2009 Nov 4. PMID:19889642 doi:10.1074/jbc.M109.069799