1HYU

CRYSTAL STRUCTURE OF INTACT AHPF

Summary for 1HYU

• Entry DOI: 10.2210/pdb1hyu/pdb
• Descriptor: ALKYL HYDROPEROXIDE REDUCTASE SUBUNIT F, SULFATE ION, CHLORIDE ION, ... (5 entities in total)
• Functional Keywords: thiol-thiolate hydrogen bond, nucleotide binding fold, thioredoxin reductase, thioredoxin, oxidoreductase
• Biological source: Salmonella typhimurium
• Total number of polymer chains: 1
• Total formula weight: 57028.79

Authors

Wood, Z.A.,Poole, L.B.,Karplus, P.A. (deposition date: 2001-01-22, release date: 2001-02-14, Last modification date: 2024-11-13)

Primary citation

Wood, Z.A.,Poole, L.B.,Karplus, P.A.
Structure of intact AhpF reveals a mirrored thioredoxin-like active site and implies large domain rotations during catalysis.
Biochemistry, 40:3900-3911, 2001

PubMed Abstract: 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.

PubMed: 11300769
DOI: 10.1021/bi002765p

Experimental method

X-RAY DIFFRACTION (2 Å)