Structure of AhpD from Mycobacterium tuberculosis, a novel enzyme with thioredoxin-like activity.Structure of AhpD from Mycobacterium tuberculosis, a novel enzyme with thioredoxin-like activity.

Structural highlights

1knc is a 3 chain structure with sequence from Mycobacterium tuberculosis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:
Resources:FirstGlance, OCA, RCSB, PDBsum

Function

[AHPD_MYCTU] Antioxidant protein with alkyl hydroperoxidase activity. Required for the reduction of the AhpC active site cysteine residues and for the regeneration of the AhpC enzyme activity.[1] [2] [3] Together with AhpC, DlaT and Lpd, constitutes an NADH-dependent peroxidase active against hydrogen and alkyl peroxides as well as serving as a peroxynitrite reductase, thus protecting the bacterium against reactive nitrogen intermediates and oxidative stress generated by the host immune system.[4] [5] [6]

Evolutionary Conservation

 

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Mycobacterium tuberculosis (Mtb) mounts a stubborn defense against oxidative and nitrosative components of the immune response. Dihydrolipoamide dehydrogenase (Lpd) and dihydrolipoamide succinyltransferase (SucB) are components of alpha-ketoacid dehydrogenase complexes that are central to intermediary metabolism. We find that Lpd and SucB support Mtb's antioxidant defense. The peroxiredoxin alkyl hydroperoxide reductase (AhpC) is linked to Lpd and SucB by an adaptor protein, AhpD. The 2.0 angstrom AhpD crystal structure reveals a thioredoxin-like active site that is responsive to lipoamide. We propose that Lpd, SucB (the only lipoyl protein detected in Mtb), AhpD, and AhpC together constitute a nicotinamide adenine dinucleotide (reduced)-dependent peroxidase and peroxynitrite reductase. AhpD thus represents a class of thioredoxin-like molecules that enables an antioxidant defense.

Metabolic enzymes of mycobacteria linked to antioxidant defense by a thioredoxin-like protein.,Bryk R, Lima CD, Erdjument-Bromage H, Tempst P, Nathan C Science. 2002 Feb 8;295(5557):1073-7. Epub 2002 Jan 17. PMID:11799204[7]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

  1. Hillas PJ, del Alba FS, Oyarzabal J, Wilks A, Ortiz De Montellano PR. The AhpC and AhpD antioxidant defense system of Mycobacterium tuberculosis. J Biol Chem. 2000 Jun 23;275(25):18801-9. PMID:10766746 doi:http://dx.doi.org/10.1074/jbc.M001001200
  2. Bryk R, Lima CD, Erdjument-Bromage H, Tempst P, Nathan C. Metabolic enzymes of mycobacteria linked to antioxidant defense by a thioredoxin-like protein. Science. 2002 Feb 8;295(5557):1073-7. Epub 2002 Jan 17. PMID:11799204 doi:10.1126/science.1067798
  3. Koshkin A, Nunn CM, Djordjevic S, Ortiz de Montellano PR. The mechanism of Mycobacterium tuberculosis alkylhydroperoxidase AhpD as defined by mutagenesis, crystallography, and kinetics. J Biol Chem. 2003 Aug 8;278(32):29502-8. Epub 2003 May 21. PMID:12761216 doi:10.1074/jbc.M303747200
  4. Hillas PJ, del Alba FS, Oyarzabal J, Wilks A, Ortiz De Montellano PR. The AhpC and AhpD antioxidant defense system of Mycobacterium tuberculosis. J Biol Chem. 2000 Jun 23;275(25):18801-9. PMID:10766746 doi:http://dx.doi.org/10.1074/jbc.M001001200
  5. Bryk R, Lima CD, Erdjument-Bromage H, Tempst P, Nathan C. Metabolic enzymes of mycobacteria linked to antioxidant defense by a thioredoxin-like protein. Science. 2002 Feb 8;295(5557):1073-7. Epub 2002 Jan 17. PMID:11799204 doi:10.1126/science.1067798
  6. Koshkin A, Nunn CM, Djordjevic S, Ortiz de Montellano PR. The mechanism of Mycobacterium tuberculosis alkylhydroperoxidase AhpD as defined by mutagenesis, crystallography, and kinetics. J Biol Chem. 2003 Aug 8;278(32):29502-8. Epub 2003 May 21. PMID:12761216 doi:10.1074/jbc.M303747200
  7. Bryk R, Lima CD, Erdjument-Bromage H, Tempst P, Nathan C. Metabolic enzymes of mycobacteria linked to antioxidant defense by a thioredoxin-like protein. Science. 2002 Feb 8;295(5557):1073-7. Epub 2002 Jan 17. PMID:11799204 doi:10.1126/science.1067798

1knc, resolution 2.00Å

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