1hyu
From Proteopedia
(New page: 200px<br /><applet load="1hyu" size="450" color="white" frame="true" align="right" spinBox="true" caption="1hyu, resolution 2.00Å" /> '''CRYSTAL STRUCTURE OF...) |
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| - | [[Image:1hyu.gif|left|200px]]<br /><applet load="1hyu" size=" | + | [[Image:1hyu.gif|left|200px]]<br /><applet load="1hyu" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1hyu, resolution 2.00Å" /> | caption="1hyu, resolution 2.00Å" /> | ||
'''CRYSTAL STRUCTURE OF INTACT AHPF'''<br /> | '''CRYSTAL STRUCTURE OF INTACT AHPF'''<br /> | ||
==Overview== | ==Overview== | ||
| - | AhpF, a homodimer of 57 kDa subunits, is a flavoenzyme which catalyzes the | + | AhpF, a homodimer of 57 kDa subunits, is a flavoenzyme which catalyzes the NADH-dependent reduction of redox-active disulfide bonds in the peroxidase AhpC, a member of the recently identified peroxiredoxin class of antioxidant enzymes. The structure of AhpF from Salmonella typhimurium at 2.0 A resolution, determined using multiwavelength anomalous dispersion, shows that the C-terminal portion of AhpF (residues 210-521) is structurally like Escherichia coli thioredoxin reductase. In addition, AhpF has an N-terminal domain (residues 1-196) formed from two contiguous thioredoxin folds, but containing just a single redox-active disulfide (Cys129-Cys132). A flexible linker (residues 197-209) connects the domains, consistent with experiments showing that the N-terminal domain acts as an appended substrate, first being reduced by the C-terminal portion of AhpF, and subsequently reducing AhpC. Modeling studies imply that an intrasubunit electron transfer accounts for the reduction of the N-terminal domain in dimeric AhpF. Furthermore, comparing the N-terminal domain with protein disulfide oxidoreductase from Pyrococcus furiosis, we describe a new class of protein disulfide oxidoreductases based on a novel mirror-image active site arrangement, with a distinct carboxylate (Glu86) being functionally equivalent to the key acid (Asp26) of E. coli thioredoxin. A final fortuitous result is that the N-terminal redox center is reduced and provides a high-resolution view of the thiol-thiolate hydrogen bond that has been predicted to stabilize the attacking thiolate in thioredoxin-like proteins. |
==About this Structure== | ==About this Structure== | ||
| - | 1HYU is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Salmonella_typhimurium Salmonella typhimurium] with SO4, CL and FAD as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1HYU is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Salmonella_typhimurium Salmonella typhimurium] with <scene name='pdbligand=SO4:'>SO4</scene>, <scene name='pdbligand=CL:'>CL</scene> and <scene name='pdbligand=FAD:'>FAD</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1HYU OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Salmonella typhimurium]] | [[Category: Salmonella typhimurium]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Karplus, P | + | [[Category: Karplus, P A.]] |
| - | [[Category: Poole, L | + | [[Category: Poole, L B.]] |
| - | [[Category: Wood, Z | + | [[Category: Wood, Z A.]] |
[[Category: CL]] | [[Category: CL]] | ||
[[Category: FAD]] | [[Category: FAD]] | ||
| Line 24: | Line 24: | ||
[[Category: thioredoxin reductase]] | [[Category: thioredoxin reductase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:06:10 2008'' |
Revision as of 11:06, 21 February 2008
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CRYSTAL STRUCTURE OF INTACT AHPF
Overview
AhpF, a homodimer of 57 kDa subunits, is a flavoenzyme which catalyzes the NADH-dependent reduction of redox-active disulfide bonds in the peroxidase AhpC, a member of the recently identified peroxiredoxin class of antioxidant enzymes. The structure of AhpF from Salmonella typhimurium at 2.0 A resolution, determined using multiwavelength anomalous dispersion, shows that the C-terminal portion of AhpF (residues 210-521) is structurally like Escherichia coli thioredoxin reductase. In addition, AhpF has an N-terminal domain (residues 1-196) formed from two contiguous thioredoxin folds, but containing just a single redox-active disulfide (Cys129-Cys132). A flexible linker (residues 197-209) connects the domains, consistent with experiments showing that the N-terminal domain acts as an appended substrate, first being reduced by the C-terminal portion of AhpF, and subsequently reducing AhpC. Modeling studies imply that an intrasubunit electron transfer accounts for the reduction of the N-terminal domain in dimeric AhpF. Furthermore, comparing the N-terminal domain with protein disulfide oxidoreductase from Pyrococcus furiosis, we describe a new class of protein disulfide oxidoreductases based on a novel mirror-image active site arrangement, with a distinct carboxylate (Glu86) being functionally equivalent to the key acid (Asp26) of E. coli thioredoxin. A final fortuitous result is that the N-terminal redox center is reduced and provides a high-resolution view of the thiol-thiolate hydrogen bond that has been predicted to stabilize the attacking thiolate in thioredoxin-like proteins.
About this Structure
1HYU is a Single protein structure of sequence from Salmonella typhimurium with , and as ligands. Full crystallographic information is available from OCA.
Reference
Structure of intact AhpF reveals a mirrored thioredoxin-like active site and implies large domain rotations during catalysis., Wood ZA, Poole LB, Karplus PA, Biochemistry. 2001 Apr 3;40(13):3900-11. PMID:11300769
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