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Trichomonas vaginalis Hmp35, a putative pore-forming hydrogenosomal membrane protein, can form a complex in yeast

Sabrina D Dyall1, Dianna C Lester, Rachel E Schneider

  • 1Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, California 90095-1489 and the Department of Chemistry and Biochemistry and the Molecular Biology Institute, UCLA, Los Angeles, California 90095-1569.

The Journal of Biological Chemistry
|May 27, 2003
PubMed

Insights

Researchers isolated the Hmp35 protein complex from Trichomonas vaginalis hydrogenosomes. This stable, abundant protein complex exhibits protease resistance and can be targeted to yeast mitochondria, suggesting conserved protein translocation machinery.

Area of Science:

  • Cell Biology
  • Parasitology
  • Protein Biochemistry

Background:

  • Hmp35 is an abundant integral membrane protein found in Trichomonas vaginalis hydrogenosomes.
  • This protein lacks known homologs and forms a stable 300-kDa complex (HMP35) within hydrogenosome membranes.

Purpose of the Study:

  • To characterize the Hmp35 protein complex, including its stability, structure, and composition.
  • To investigate the protein's potential function and its targeting mechanisms.

Main Methods:

  • Blue native gel electrophoresis to assess complex stability.
  • Protease resistance assays.
  • Protein purification using His-tagged expression and nickel-agarose chromatography.
  • Heterologous targeting into yeast mitochondria.

Main Results:

  • The HMP35 complex is highly stable, resisting 2 M NaCl and 5 M urea, and the endogenous Hmp35 protein is largely protease-resistant.
  • Hmp35 possesses a beta-sheet structure, predicted transmembrane domains, and numerous cysteine residues, potentially involved in cation coordination.
  • The purified 300-kDa complex comprises predominantly Hmp35, with minor amounts of other proteins, indicating Hmp35 exists as an oligomer.
  • Hmp35 can be successfully targeted into yeast mitochondria, irrespective of sequence homology.

Conclusions:

  • Hmp35 forms a stable, oligomeric complex within hydrogenosomes with unique structural features.
  • The conserved protein translocation machinery between hydrogenosomes and mitochondria is highlighted by the heterologous targeting of Hmp35.
  • Further research into Hmp35's function and its role in hydrogenosome biology is warranted.

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