1hyu
From Proteopedia
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'''CRYSTAL STRUCTURE OF INTACT AHPF''' | '''CRYSTAL STRUCTURE OF INTACT AHPF''' | ||
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[[Category: Poole, L B.]] | [[Category: Poole, L B.]] | ||
[[Category: Wood, Z A.]] | [[Category: Wood, Z A.]] | ||
| - | [[Category: | + | [[Category: Nucleotide binding fold]] |
| - | [[Category: | + | [[Category: Thiol-thiolate hydrogen bond]] |
| - | [[Category: | + | [[Category: Thioredoxin]] |
| - | [[Category: | + | [[Category: Thioredoxin reductase]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 19:22:30 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 16:22, 2 May 2008
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. 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 Page seeded by OCA on Fri May 2 19:22:30 2008
