Assembly factor Omp85 recognizes its outer membrane protein substrates by a species-specific C-terminal motif

V.M.V. Robert, E.B. Volokhina, F. Senf, M.P. Bos, P. van Gelder, J.P.M. Tommassen

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Integral β-barrel proteins are found in the outer membranes of Gram-negative bacteria, mitochondria, and chloroplasts. The assembly of these proteins requires a proteinaceous apparatus of which Omp85 is an evolutionary conserved central component. To study its molecular mechanism, we have produced Omp85 from Escherichia coli in inclusion bodies and refolded it in vitro. The interaction of Omp85 with its substrate proteins was studied in lipid-bilayer experiments, where it formed channels. The properties of these channels were affected upon addition of unfolded outer-membrane proteins (OMPs) or synthetic peptides corresponding to their C-terminal signature sequences. The interaction exhibited species specificity, explaining the inefficient assembly of OMPs from Neisseria in E. coli. Accordingly, the in vivo assembly of the neisserial porin PorA into the E. coli outer membrane was accomplished after adapting its signature sequence. These results demonstrate that the Omp85 assembly machinery recognizes OMPs by virtue of their C-terminal signature sequence.
Original languageEnglish
Article numbere377
Pages (from-to)1984-1995
Number of pages12
JournalPloS Biology [E]
Volume4
Issue number11
DOIs
Publication statusPublished - 2006

Keywords

  • Molecular biology
  • Life sciences
  • Microbiology
  • Cell biology

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