AhpC of the mycobacterial antioxidant defense system and its interaction with its reducing partner Thioredoxin-C

Sci Rep. 2017 Jul 11;7(1):5159. doi: 10.1038/s41598-017-05354-5.

Abstract

Despite the highly oxidative environment of the phagosomal lumen, the need for maintaining redox homeostasis is a critical aspect of mycobacterial biology. The pathogens are equipped with the sophisticated thioredoxin- (Trx) and peroxiredoxin system, including TrxC and the alkyl hydroperoxide reductase subunit C (AhpC), whereby TrxC is one of the reducing partners of AhpC. Here we visualize the redox modulated dodecamer ring formation of AhpC from Mycobacterium bovis (BCG strain; MbAhpC) using electron microscopy and present novel insights into the unique N-terminal epitope (40 residues) of mycobacterial AhpC. Truncations and amino acid substitutions of residues in the unique N-terminus of MbAhpC provide insights into their structural and enzymatic roles, and into the evolutionary divergence of mycobacterial AhpC versus that of other bacteria. These structural details shed light on the epitopes and residues of TrxC which contributes to its interaction with AhpC. Since human cells lack AhpC, the unique N-terminal epitope of mycobacterial AhpC as well as the MbAhpC-TrxC interface represent an ideal drug target.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Substitution
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Binding Sites
  • Dynamic Light Scattering
  • Epitopes / chemistry
  • Homeostasis
  • Hydrogen Peroxide / chemistry
  • Microscopy, Electron
  • Models, Molecular
  • Molecular Docking Simulation
  • Mycobacterium bovis / chemistry
  • Mycobacterium bovis / genetics
  • Mycobacterium bovis / metabolism*
  • Oxidation-Reduction
  • Peroxiredoxins / chemistry*
  • Peroxiredoxins / genetics
  • Peroxiredoxins / metabolism*
  • Protein Binding
  • Protein Conformation
  • Protein Multimerization
  • Thioredoxins / chemistry*
  • Thioredoxins / metabolism*

Substances

  • Bacterial Proteins
  • Epitopes
  • Thioredoxins
  • Hydrogen Peroxide
  • Peroxiredoxins