2a8g

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Revision as of 05:51, 21 November 2007

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spinqualitylabelsall models 2a8g, resolution 1.990Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Structure of Avidin in complex with the ligand deoxyguanosine

Overview

Oxidative damage of DNA results in the formation of many products, including 8-oxodeoxyguanosine, which has been used as a marker to quantify, DNA damage. Earlier studies have demonstrated that avidin, a protein, prevalent in egg-white and which has high affinity for the vitamin biotin, binds to 8-oxodeoxyguanosine and related bases. In this study, we have, determined crystal structures of avidin in complex with, 8-oxodeoxyguanosine and 8-oxodeoxyadenosine. In each case, the base is, observed to bind within the biotin-binding site of avidin. However, the, mode of association between the bases and the protein varies and, unlike, in the avidin:biotin complex, complete ordering of the protein in this, region does not accompany binding. Fluorescence studies indicate that in, solution the individual bases, and a range of oligonucleotides, bind to, avidin with micromolar affinity. Only one of the modes of binding observed, is consistent with recognition of oxidised purines when incorporated, within a DNA oligomer, and from this structure a model is proposed for the, selective binding of avidin to DNA containing oxidatively damaged, deoxyguanosine. These studies illustrate the molecular basis by which, avidin might act as a marker of DNA damage, although the low levels of, binding observed are inconsistent with the recognition of oxidised purines, forming a major physiological role for avidin.

About this Structure

2A8G is a Single protein structure of sequence from Gallus gallus with NAG and GNG as ligands. Full crystallographic information is available from OCA.

Reference

Recognition of oxidatively modified bases within the biotin-binding site of avidin., Conners R, Hooley E, Clarke AR, Thomas S, Brady RL, J Mol Biol. 2006 Mar 17;357(1):263-74. Epub 2006 Jan 6. PMID:16413579

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