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Oxidation of the Mycobacterium tuberculosis key virulence factor protein tyrosine phosphatase A (MptpA) reduces its

Anna Niesteruk1, Sridhar Sreeramulu1, Hendrik R A Jonker1

  • 1Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt am Main, Institute for Organic Chemistry and Chemical Biology, Frankfurt am Main, Germany.

FEBS Letters
|April 9, 2022
PubMed

Insights

Oxidative stress inactivates Mycobacterium tuberculosis phosphatase MptpA by modifying its catalytic cysteine. This oxidation acts as a redox switch, regulating MptpA

Area of Science:

  • Biochemistry
  • Microbiology
  • Structural Biology

Background:

  • Mycobacterium tuberculosis tyrosine-specific phosphatase MptpA and kinase PtkA are potential drug targets.
  • Their interaction with host defense mechanisms in macrophages is known, but their regulatory mechanisms are unclear.

Purpose of the Study:

  • To investigate the role of post-translational oxidation in regulating MptpA activity.
  • To understand the functional mechanism of MptpA under oxidative stress.

Main Methods:

  • Treatment of MptpA with hydrogen peroxide (H2O2) and sodium bicarbonate (NaHCO3) to mimic oxidative stress.
  • Analysis of structural and conformational changes, including catalytic cysteine oxidation and D-loop rearrangement.

Main Results:

  • Oxidative stress conditions led to the oxidation of the catalytic cysteine (C11) in MptpA.
  • A conformational rearrangement of the D-loop occurred, repositioning tyrosine 128 (Y128).
  • This resulted in a temporarily inactive, preclosed state of the phosphatase.

Conclusions:

  • The catalytic cysteine in MptpA's P-loop functions as a redox switch.
  • Post-translational oxidation regulates MptpA phosphatase activity, impacting its role in host-pathogen interactions.
Keywords:
Mycobacterium tuberculosiscysteine-redox regulationnuclear magnetic resonance spectroscopyprotein oxidationprotein tyrosine phosphatasereactive oxygen species

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