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Functional characterization of methionine sulfoxide reductases from Leptospira interrogans

Natalia Sasoni1, Matías D Hartman1, Sergio A Guerrero1

  • 1Laboratorio de Enzimología Molecular, Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Santa Fe, Argentina; Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina.

Biochimica Et Biophysica Acta. Proteins and Proteomics
|November 26, 2020
PubMed
Abstract

Insights

Leptospira interrogans possesses methionine sulfoxide reductases (Msr) enzymes that repair oxidized proteins. These enzymes, MsrA and MsrB, are crucial for maintaining cellular function and protecting macromolecules in this pathogen.

Area of Science:

  • Microbiology
  • Biochemistry
  • Redox Biology

Background:

  • Methionine oxidation produces R and S methionine sulfoxide (MetSO) isomers.
  • Methionine sulfoxide reductases (Msr) enzymes repair MetSO, impacting protein structure and function.
  • The presence and function of Msr enzymes in Leptospira interrogans were previously unknown.

Purpose of the Study:

  • To identify and characterize Msr enzymes in Leptospira interrogans.
  • To investigate the enzymatic activity and substrate specificity of L. interrogans MsrA and MsrB.
  • To understand the role of Msr enzymes in the redox metabolism of L. interrogans.

Main Methods:

  • Genes for putative MsrA and MsrB were identified in the L. interrogans genome.
  • Recombinant Msr proteins were expressed and purified.
  • Enzymatic activity assays were performed using various reducing substrates and MetSO isomers.

Main Results:

  • Recombinant L. interrogans MsrB reduced Met(R)SO, functioning as a 1-Cys Msr and partially restoring catalase activity.
  • Recombinant L. interrogans MsrA enzymes reduced Met(S)SO via the thioredoxin system and showed higher efficiency than MsrB.
  • Both MsrA and MsrB exhibited dual localization in the cytoplasm and periplasm.

Conclusions:

  • L. interrogans possesses functional Msr enzymes (MsrA and MsrB) involved in repairing oxidized macromolecules.
  • These findings reveal a novel metabolic pathway for redox homeostasis in L. interrogans.
  • The identified Msr enzymes are critical for protecting the pathogen from oxidative damage.
Keywords:
GlutaredoxinLeptospiraMethionine sulfoxide reductaseRedox metabolismThioredoxin

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