2a8g

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(New page: 200px<br /><applet load="2a8g" size="450" color="white" frame="true" align="right" spinBox="true" caption="2a8g, resolution 1.990&Aring;" /> '''Structure of Avidin...)
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caption="2a8g, resolution 1.990&Aring;" />
caption="2a8g, resolution 1.990&Aring;" />
'''Structure of Avidin in complex with the ligand deoxyguanosine'''<br />
'''Structure of Avidin in complex with the ligand deoxyguanosine'''<br />
==Overview==
==Overview==
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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.
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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==
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2A8G 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 GNG as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2A8G OCA].
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2A8G 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=GNG:'>GNG</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2A8G OCA].
==Reference==
==Reference==
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[[Category: Gallus gallus]]
[[Category: Gallus gallus]]
[[Category: Single protein]]
[[Category: Single protein]]
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[[Category: Brady, R.L.]]
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[[Category: Brady, R L.]]
[[Category: Conners, R.]]
[[Category: Conners, R.]]
[[Category: Hooley, E.]]
[[Category: Hooley, E.]]
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[[Category: beta barrel]]
[[Category: beta barrel]]
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''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 07:59:13 2007''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:24:38 2008''

Revision as of 14:24, 21 February 2008


2a8g, resolution 1.990Å

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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 and 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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