1snh
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Solution structure of the DNA Decamer Duplex Containing Double TG Mismatches of Cis-syn Cyclobutane Pyrimidine Dimer
OverviewOverview
The cis-syn cyclobutane pyrimidine dimer (CPD) is a cytotoxic, mutagenic, and carcinogenic DNA photoproduct and is repaired by the nucleotide, excision repair (NER) pathway in mammalian cells. The XPC-hHR23B complex, as the initiator of global genomic NER binds to sites of certain kinds of, DNA damage. Although CPDs are rarely recognized by the XPC-hHR23B complex, the presence of mismatched bases opposite a CPD significantly increased, the binding affinity of the XPC-hHR23B complex to the CPD. In order to, decipher the properties of the DNA structures that determine the binding, affinity for XPC-hHR23B to DNA, we carried out structural analyses of the, various types of CPDs by NMR spectroscopy. The DNA duplex which contains a, single 3' T*G wobble pair in a CPD (CPD/GA duplex) induces little, conformational distortion. However, severe distortion of the helical, conformation occurs when a CPD contains double T*G wobble pairs (CPD/GG, duplex) even though the T residues of the CPD form stable hydrogen bonds, with the opposite G residues. The helical bending angle of the CPD/GG, duplex was larger than those of the CPD/GA duplex and properly matched, CPD/AA duplex. The fluctuation of the backbone conformation and, significant changes in the widths of the major and minor grooves at the, double T*G wobble paired site were also observed in the CPD/GG duplex., These structural features were also found in a duplex that contains the, (6-4) adduct, which is efficiently recognized by the XPC-hHR23B complex., Thus, we suggest that the unique structural features of the DNA double, helix (that is, helical bending, flexible backbone conformation, and, significant changes of the major and/or minor grooves) might be important, factors in determining the binding affinity of the XPC-hHR23B complex to, DNA.
About this StructureAbout this Structure
1SNH is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
ReferenceReference
NMR structure of the DNA decamer duplex containing double T*G mismatches of cis-syn cyclobutane pyrimidine dimer: implications for DNA damage recognition by the XPC-hHR23B complex., Lee JH, Park CJ, Shin JS, Ikegami T, Akutsu H, Choi BS, Nucleic Acids Res. 2004 Apr 30;32(8):2474-81. Print 2004. PMID:15121904
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