1qmv
From Proteopedia
(New page: 200px<br /><applet load="1qmv" size="450" color="white" frame="true" align="right" spinBox="true" caption="1qmv, resolution 1.7Å" /> '''THIOREDOXIN PEROXIDAS...) |
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| - | [[Image:1qmv.gif|left|200px]]<br /><applet load="1qmv" size=" | + | [[Image:1qmv.gif|left|200px]]<br /><applet load="1qmv" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1qmv, resolution 1.7Å" /> | caption="1qmv, resolution 1.7Å" /> | ||
'''THIOREDOXIN PEROXIDASE B FROM RED BLOOD CELLS'''<br /> | '''THIOREDOXIN PEROXIDASE B FROM RED BLOOD CELLS'''<br /> | ||
==Overview== | ==Overview== | ||
| - | BACKGROUND: The peroxiredoxins (Prxs) are an emerging family of | + | BACKGROUND: The peroxiredoxins (Prxs) are an emerging family of multifunctional enzymes that exhibit peroxidase activity in vitro, and in vivo participate in a range of cellular processes known to be sensitive to reactive oxygen species. Thioredoxin peroxidase B (TPx-B), a 2-Cys type II Prx from erythrocytes, promotes potassium efflux and down-regulates apoptosis and the recruitment of monocytes by endothelial tissue. RESULTS: The crystal structure of human decameric TPx-B purified from erythrocytes has been determined to 1.7 [corrected)] A resolution. The structure is a toroid comprising five dimers linked end-on through predominantly hydrophobic interactions, and is proposed to represent an intermediate in the in vivo reaction cycle. In the crystal structure, Cys51, the site of peroxide reduction, is oxidised to cysteine sulphinic acid. The residue Cys172, lies approximately 10 A away from Cys51 [corrected]. CONCLUSIONS: The oxidation of Cys51 appears to have trapped the structure into a stable decamer, as confirmed by sedimentation analysis. A comparison with two previously reported dimeric Prx structures reveals that the catalytic cycle of 2-Cys Prx requires significant conformational changes that include the unwinding of the active-site helix and the movement of four loops. It is proposed that the stable decamer forms in vivo under conditions of oxidative stress. Similar decameric structures of TPx-B have been observed by electron microscopy, which show the protein associated with the erythrocyte membrane. |
==About this Structure== | ==About this Structure== | ||
| - | 1QMV is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http:// | + | 1QMV is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QMV OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Errington, N.]] | [[Category: Errington, N.]] | ||
| - | [[Category: Isupov, N | + | [[Category: Isupov, N N.]] |
| - | [[Category: Lebedev, A | + | [[Category: Lebedev, A A.]] |
| - | [[Category: Littlechild, J | + | [[Category: Littlechild, J A.]] |
[[Category: Schroder, E.]] | [[Category: Schroder, E.]] | ||
| - | [[Category: Vagin, A | + | [[Category: Vagin, A A.]] |
[[Category: peroxidase]] | [[Category: peroxidase]] | ||
[[Category: peroxiredoxin]] | [[Category: peroxiredoxin]] | ||
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[[Category: thioredoxin]] | [[Category: thioredoxin]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:41:26 2008'' |
Revision as of 12:41, 21 February 2008
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THIOREDOXIN PEROXIDASE B FROM RED BLOOD CELLS
Overview
BACKGROUND: The peroxiredoxins (Prxs) are an emerging family of multifunctional enzymes that exhibit peroxidase activity in vitro, and in vivo participate in a range of cellular processes known to be sensitive to reactive oxygen species. Thioredoxin peroxidase B (TPx-B), a 2-Cys type II Prx from erythrocytes, promotes potassium efflux and down-regulates apoptosis and the recruitment of monocytes by endothelial tissue. RESULTS: The crystal structure of human decameric TPx-B purified from erythrocytes has been determined to 1.7 [corrected)] A resolution. The structure is a toroid comprising five dimers linked end-on through predominantly hydrophobic interactions, and is proposed to represent an intermediate in the in vivo reaction cycle. In the crystal structure, Cys51, the site of peroxide reduction, is oxidised to cysteine sulphinic acid. The residue Cys172, lies approximately 10 A away from Cys51 [corrected]. CONCLUSIONS: The oxidation of Cys51 appears to have trapped the structure into a stable decamer, as confirmed by sedimentation analysis. A comparison with two previously reported dimeric Prx structures reveals that the catalytic cycle of 2-Cys Prx requires significant conformational changes that include the unwinding of the active-site helix and the movement of four loops. It is proposed that the stable decamer forms in vivo under conditions of oxidative stress. Similar decameric structures of TPx-B have been observed by electron microscopy, which show the protein associated with the erythrocyte membrane.
About this Structure
1QMV is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Crystal structure of decameric 2-Cys peroxiredoxin from human erythrocytes at 1.7 A resolution., Schroder E, Littlechild JA, Lebedev AA, Errington N, Vagin AA, Isupov MN, Structure. 2000 Jun 15;8(6):605-15. PMID:10873855
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