178d | pdb_0000178d
CRYSTAL STRUCTURE OF A DNA DUPLEX CONTAINING 8-HYDROXYDEOXYGUANINE.ADENINE BASE-PAIRS
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Overview
The crystal structure of the oligonucleotide d(CGCAAATTO8GGCG), containing the chemically modified base 8-hydroxydeoxyguanine (O8G), has been determined at 2.5-A resolution and refined to a crystallographic R-factor of 16.8%. The B-type DNA helix contains standard Watson-Crick base pairs except at the mismatch sites, where O8G adopts a syn conformation and forms hydrogen bonds to adenine in the anti conformation. The thermodynamic stability of the duplex was found by UV melting techniques to be intermediate between the native oligonucleotide d(CGCAAATTTGCG) and an oligonucleotide containing A.G mispairs d(CGCAAATTGGCG). Comparison of the structure of the O8G(syn).A(anti) base pair with those of Watson-Crick base pairs has given a reason why O8G.A base pairs are not well repaired by DNA proofreading enzymes.
About this Structure
178D is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Crystal structure of a DNA duplex containing 8-hydroxydeoxyguanine-adenine base pairs., McAuley-Hecht KE, Leonard GA, Gibson NJ, Thomson JB, Watson WP, Hunter WN, Brown T, Biochemistry. 1994 Aug 30;33(34):10266-70. PMID:8068665
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