A novel mitosomal β-barrel outer membrane protein in Entamoeba

Herbert J. Santos, Kenichiro Imai, Takashi Makiuchi, Kentaro Tomii, Paul Horton, Akira Nozawa, Mohamed Ibrahim, Yuzuru Tozawa, Tomoyoshi Nozaki

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Entamoeba possesses a highly divergent mitochondrion-related organelle known as the mitosome. Here, we report the discovery of a novel protein in Entamoeba, which we name Mitosomal β-barrel Outer Membrane Protein of 30 kDa (MBOMP30). Initially identified through in silico analysis, we experimentally confirmed that MBOMP30 is indeed a β-barrel protein. Circular dichroism analysis showed MBOMP30 has a predominant β-sheet structure. Localization to Entamoeba histolytica mitosomes was observed through Percoll-gradient fractionation and immunofluorescence assay. Mitosomal membrane integration was demonstrated by carbonate fractionation, proteinase K digestion, and immunoelectron microscopy. Interestingly, the deletion of the putative β-signal, a sequence believed to guide β-barrel outer membrane protein (BOMP) assembly, did not affect membrane integration, but abolished the formation of a ∼240 kDa complex. MBOMP30 represents only the seventh subclass of eukaryotic BOMPs discovered to date and lacks detectable homologs outside Entamoeba, suggesting that it may be unique to Entamoeba mitosomes.

Original languageEnglish
Article number8545
JournalScientific reports
Publication statusPublished - 2015

All Science Journal Classification (ASJC) codes

  • General


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