2a5b: Difference between revisions
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'''Avidin complexed with 8-oxodeoxyguanosine''' | '''Avidin complexed with 8-oxodeoxyguanosine''' | ||
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[[Category: Thomas, S.]] | [[Category: Thomas, S.]] | ||
[[Category: 8-oxodeoxyguanosine]] | [[Category: 8-oxodeoxyguanosine]] | ||
[[Category: | [[Category: Avidin]] | ||
[[Category: | [[Category: Damaged dna]] | ||
[[Category: | [[Category: X-ray crystallography]] | ||
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Revision as of 15:37, 3 May 2008
Avidin complexed with 8-oxodeoxyguanosine
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
2A5B is a Single protein structure of sequence from Gallus gallus. 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 Page seeded by OCA on Sat May 3 18:37:31 2008
