2a5c: Difference between revisions
New page: left|200px<br /><applet load="2a5c" size="450" color="white" frame="true" align="right" spinBox="true" caption="2a5c, resolution 2.500Å" /> '''Structure of Avidin... |
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[[Image:2a5c.gif|left|200px]]<br /><applet load="2a5c" size=" | [[Image:2a5c.gif|left|200px]]<br /><applet load="2a5c" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="2a5c, resolution 2.500Å" /> | caption="2a5c, resolution 2.500Å" /> | ||
'''Structure of Avidin in complex with the ligand 8-oxodeoxyadenosine'''<br /> | '''Structure of Avidin in complex with the ligand 8-oxodeoxyadenosine'''<br /> | ||
==Overview== | ==Overview== | ||
Oxidative damage of DNA results in the formation of many products, including 8-oxodeoxyguanosine, which has been used as a marker to quantify | 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== | ==About this Structure== | ||
2A5C is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus] with NAG and 8DA as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | 2A5C is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus] with <scene name='pdbligand=NAG:'>NAG</scene> and <scene name='pdbligand=8DA:'>8DA</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2A5C OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Gallus gallus]] | [[Category: Gallus gallus]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Brady, R | [[Category: Brady, R L.]] | ||
[[Category: Conners, R.]] | [[Category: Conners, R.]] | ||
[[Category: Hooley, E.]] | [[Category: Hooley, E.]] | ||
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[[Category: x-ray crystallography]] | [[Category: x-ray crystallography]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:23:44 2008'' | ||
Revision as of 17:23, 21 February 2008
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Structure of Avidin in complex with the ligand 8-oxodeoxyadenosine
OverviewOverview
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 StructureAbout this Structure
2A5C is a Single protein structure of sequence from Gallus gallus with and as ligands. Full crystallographic information is available from OCA.
ReferenceReference
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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