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Last modified: 26 February 1999

Aldehyde ferredoxin oxidoreductase family
Prosthetic group Formal oxidation states
Fe4S4 image
[Fe4S4](SgammaCys)4
[Fe4S4]+; [Fe4S4]2+
Wco image

W(Smolybdopterin)4
WV; WVI

MgII
mononuclear Fe image

Fe(NepsilonHis)2(OepsilonGlu)2
FeII

Enzymes of the aldehyde ferredoxin oxidoreductase (AOR) family [1, 2] contain, as a rule, a tungsten cofactor and an [Fe4S4] cluster and catalyse the interconversion of aldehydes to carboxylates (1). This family includes AOR, formaldehyde ferredoxin oxidoreductase (FOR), glyceraldehyde­3­phosphate ferredoxin oxidoreductase (GAPOR), all isolated from hyperthermophilic archea [2]; carboxylic acid reductase found in clostridia [3]; and hydroxycarboxylate viologen oxidoreductase from Proteus vulgaris, the sole member of the AOR family containing molybdenum [4]. GAPOR is thought to be involved in glycolysis [5], but the functions of the other proteins are not yet clear. AOR has been proposed to be the primary enzyme responsible for oxidising the aldehydes that are produced by the 2­keto acid oxidoreductases [6].

The 3­D structures of Pyrococcus furiosus AOR [7] and FOR [8] have been determined. AOR is a homodimer with each subunit containing one tungsten centre and a [Fe4S4] cluster, and a single iron atom at the dimer interface (Figure 1AOR). Each subunit folds into three domains. Domain I (residues 1-210) contains a 12­stranded antiparallel ß­barrel; domains II (residues 211-417) and III (residues 418-605) are mainly­alpha. The fold of domain I exhibits a pseudo twofold symmetry axis which approximately coincides with the twofold axis of the tungsten cofactor.

The tungsten atom is symmetrically coordinated, with a distorted square pyramidal coordination geometry, by the four dithiolene sulphurs of the two molybdopterins. No oxo groups or protein ligands were found to be coordinated to the tungsten. The two molybdopterins are also linked through their phosphate groups to the same magnesium ion (Figure 1AOR h).

Aldehyde ferredoxin oxidoreductase family in enzyme databases

ENZYME LIGAND BRENDA Official name Alternative name(s)
1.2.99.6 1.2.99.6
-
 Carboxylate reductase

Aldehyde ferredoxin oxidoreductase family in SWISS­PROT/TREMBL

AOR_PYRFU Tungsten­containing aldehyde:ferredoxin oxidoreductase; Pyrococcus furiosus
FOR_THELI Formaldehyde:ferredoxin oxidoreductase; Thermococcus litoralis
YDHV_ECOLI Hypothetical 77.9 kD protein in ribE-pykF intergenic region; Escherichia coli
O30212 Aldehyde:ferredoxin oxidoreductase (AOR­1); Archaeoglobus fulgidus
O30159 Aldehyde:ferredoxin oxidoreductase (AOR­2); Archaeoglobus fulgidus
O29907 Aldehyde:ferredoxin oxidoreductase (AOR­3); Archaeoglobus fulgidus
O28003 Aldehyde:ferredoxin oxidoreductase (AOR­4); Archaeoglobus fulgidus

Aldehyde ferredoxin oxidoreductase family in 3­D databases

Aldehyde oxidoreductase contains a [Fe4S4] cluster and a tungsten coordinated by the two molybdopterins (see Figure 1AOR).

PDB scop BSM RELI
Base		 Header MMS Abstract ¹
1aor 1aor 1aor 1aor Aldehyde ferredoxin oxidoreductase (complex with Fe3+ and Na+·3H2O); Pyrococcus furiosus MS6MT12

¹ Macromolecular Structures abstract. Full text is available to BioMedNet Members

References

  1. Kletzin, A. and Adams, M.W.W. (1996) Tungsten in biological systems. FEMS Microbiol. Rev. 18, 5-63.
  2. Kisker, C., Schindelin, H. and Rees, D.C. (1997) Molybdenum­cofactor-containing enzymes: structure and mechanism. Annu. Rev. Biochem. 66, 233-267.
  3. White, H., Strobl, G., Feicht, R. and Simon, H. (1989) Carboxylic acid reductase: a new tungsten enzyme catalyses the reduction of non­activated carboxylic acids to aldehydes. Eur. J. Biochem. 184, 89-96.
  4. Trautwein, T., Krauss, F., Lottspeich, F. and Simon, H. (1994) The (2R)­hydroxycarboxylate­viologen­oxidoreductase from Proteus vulgaris is a molybdenum­containing iron-sulphur protein. Eur. J. Biochem. 222, 1025-1032.
  5. Mukund, S. and Adams, M.W.W. (1995) Glyceraldehyde­3­phosphate ferredoxin oxidoreductase, a novel tungsten­containing enzyme with a potential glycolytic role in the hyperthermophilic archaeon Pyrococcus furiosus. J. Biol. Chem. 270, 8389-8392.
  6. Ma, K., Hutchins, A., Sung, S.­J.S. and Adams, M.W.W. (1997) Pyruvate ferredoxin oxidoreductase from the hyperthermophilic archaeon, Pyrococcus furiosus, functions as a CoA­dependent pyruvate decarboxylase. Proc. Natl. Acad. Sci. USA 94, 9608-9613.
  7. Chan, M.K., Mukund, S., Kletzin, A., Adams, M.W.W. and Rees, D.C. (1995) Structure of a hyperthermophilic tungstopterin enzyme, aldehyde ferredoxin oxidoreductase. Science 267, 1463-1469.
  8. Hu, Y., Faham, S., Roy, R., Adams, M.W.W. and Rees, D.C. (1999) Formaldehyde ferredoxin oxidoreductase from Pyrococcus furiosus: The 1.85 Å resolution crystal structure and its mechanistic implications. J. Mol. Biol. 286, 899-914.
Bibliography on structural studies of aldehyde ferredoxin oxidoreductase family