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Updated: Jun 18, 2025

Analysis of the Expression and Complexes Assembly of the Mitochondrial Respiratory Chain Proteins in the Fission Yeast Schizosaccharomyces pombe
08:08

Analysis of the Expression and Complexes Assembly of the Mitochondrial Respiratory Chain Proteins in the Fission Yeast Schizosaccharomyces pombe

Published on: May 2, 2025

199

Characterization of the SUF FeS cluster synthesis machinery in the amitochondriate eukaryote Monocercomonoides exilis

Priscila Peña-Diaz1, Joseph J Braymer2, Vojtěch Vacek1

  • 1Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25250 Vestec, Czech Republic.

Current Biology : CB
|August 1, 2024
PubMed

Insights

Monocercomonoides exilis utilizes a unique bacterial SUF system for iron-sulfur (FeS) cluster biogenesis, replacing its lost mitochondria. This study confirms the functional FeS cluster assembly of these eukaryotic SUF proteins.

Area of Science:

  • Eukaryotic molecular biology
  • Biochemistry of iron-sulfur cluster assembly

Background:

  • Monocercomonoides exilis is the first known amitochondriate eukaryote.
  • Mitochondrial iron-sulfur cluster (ISC) machinery was replaced by a bacterial SUF system in M. exilis.
  • The precise mechanism of this eukaryotic SUF system for FeS cluster biogenesis was previously uncharacterized.

Purpose of the Study:

  • To biochemically characterize the Monocercomonoides exilis SUF system for iron-sulfur (FeS) cluster assembly.
  • To investigate the in vivo and in vitro interactions and functions of M. exilis SUF proteins.
  • To provide insights into the molecular mechanism of this unique eukaryotic FeS cluster biogenesis pathway.

Main Methods:

  • Expressed M. exilis SUF genes in Escherichia coli to assess FeS cluster loading into the IscR reporter protein.
  • Investigated in vivo interactions between M. exilis Suf proteins and E. coli Suf proteins using co-immunoprecipitation.
  • Characterized the in vitro assembly, composition, and FeS binding properties of M. exilis Suf protein complexes.

Main Results:

  • M. exilis SUF genes functionally support FeS cluster loading in E. coli.
  • M. exilis Suf proteins (MeSufB, MeSufC, MeSufDSU) interact with each other and with E. coli Suf proteins in vivo.
  • In vitro, M. exilis Suf proteins form dynamic, oligomeric complexes (e.g., MeSufBC) that bind FeS clusters, with assembly influenced by adenosine nucleotides and MeSufDSU.

Conclusions:

  • The M. exilis SUF proteins possess biochemical properties enabling them to function as a complete FeS cluster assembly system.
  • This study elucidates the molecular mechanism of a unique eukaryotic SUF system essential for life in an amitochondriate organism.
  • The findings highlight the adaptability of cellular machinery through horizontal gene transfer and subsequent functional integration.
Keywords:
FeS clustersSUF systemamitochondriatefunctional protistologyprotist

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