Topologies of Complexes Containing O6-Alkylguanine-DNA Alkyltransferase and DNA

JOURNAL OF MOLECULAR BIOLOGY

卷:389

Article

Adams, Claire A.^1,2  Melikishvili, Manana^1,2  Rodgers, David W.^1,2  Rasimas, Joseph J.³  Pegg, Anthony E.³  Fried, Michael G.^1,2 

[1] Univ Kentucky, Dept Mol & Cellular Biochem, Lexington, KY 40536 USA

[2] Univ Kentucky, Struct Biol Ctr, Lexington, KY 40536 USA

[3] Penn State Univ, Dept Mol Physiol, Coll Med, Hershey, PA 17033 USA

关键词: O-6-alkylguanine-DNA alkyltransferase;    methylguanine methyltransferase;    DNA repair;    binding cooperativity;    protein contacts;   

DOI  :  10.1016/j.jmb.2009.03.067

来源: Elsevier

【 摘 要 】

The mutagenic and cytotoxic effects of many alkylating agents are reduced by O-6-alkylguanine-DNA alkyltransferase (AGT). In humans, this protein not only protects the integrity of the genome, but also contributes to the resistance of tumors to DNA-alkylating chemotherapeutic agents. Here we describe and test models for cooperative multiprotein complexes of AGT with single-stranded and duplex DNAs that are based on in vitro binding data and the crystal structure of a 1:1 AGT-DNA complex. These models predict that cooperative assemblies contain a three-start helical array of proteins with dominant protein-protein interactions between the amino-terminal face of protein n and the carboxy-terminal face of protein n+3, and they predict that binding duplex DNA does not require large changes in B-form DNA geometry. Experimental tests using protein cross-linking analyzed by mass spectrometry, electrophoretic and analytical ultracentrifugation binding assays, and topological analyses with closed circular DNA show that the properties of multiprotein AGT-DNA complexes are consistent with these predictions. (C) 2009 Elsevier Ltd. All rights reserved.

【 授权许可】

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