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A conserved loop sequence of the proteasome system depupylase Dop regulates substrate selectivity in Mycobacterium

Jin Hee Yoo1, Shoshanna C Kahne1, K Heran Darwin1

  • 1Department of Microbiology, New York University School of Medicine, New York, New York, USA.

The Journal of Biological Chemistry
|September 13, 2022
PubMed

Insights

Mycobacteria use a prokaryotic ubiquitin-like protein (Pup) for protein degradation. Mutations in the Dop enzyme

Area of Science:

  • Molecular Biology
  • Microbiology
  • Biochemistry

Background:

  • Mycobacteria utilize a proteasome system for protein degradation, distinct from eukaryotes as it doesn't use ubiquitin.
  • Instead, they employ a prokaryotic ubiquitin-like protein (Pup) for post-translational modification, marking proteins for proteolysis.
  • Pupylation is catalyzed by PafA and reversed by Dop, an enzyme structurally similar to PafA.

Purpose of the Study:

  • To investigate the function of a conserved disordered loop in the Dop enzyme.
  • To understand the role of this loop in substrate selectivity during pupylation in Mycobacterium tuberculosis.

Main Methods:

  • Generated mutant Mycobacterium tuberculosis strains with deletions in discrete sequences of the Dop loop.
  • Assessed the pupylome profiles in these mutant strains.
  • Analyzed the impact of overexpressing mutant dop alleles on pupylation.

Main Results:

  • Various mutations within the Dop loop led to altered pupylome profiles.
  • These alterations were particularly evident when mutant dop alleles were overexpressed.
  • The findings indicate a role for conserved amino acids in the Dop loop.

Conclusions:

  • The conserved amino acids within the Dop loop are crucial for its function.
  • These residues likely play a significant role in determining Dop's substrate selectivity.
  • This research sheds light on the regulation of protein degradation in mycobacteria.
Keywords:
Mycobacterium tuberculosisdepupylationproteasomepupylation

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