Mutational and topological analysis of the Escherichia coli BamA protein

Research output: Contribution to journalArticle

External organisations

  • Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom.

Abstract

The multi-protein β-barrel assembly machine (BAM) of Escherichia coli is responsible for the folding and insertion of β-barrel containing integral outer membrane proteins (OMPs) into the bacterial outer membrane. An essential component of this complex is the BamA protein, which binds unfolded β-barrel precursors via the five polypeptide transport-associated (POTRA) domains in its N-terminus. The C-terminus of BamA contains a β-barrel domain, which tethers BamA to the outer membrane and is also thought to be involved in OMP insertion. Here we mutagenize BamA using linker scanning mutagenesis and demonstrate that all five POTRA domains are essential for BamA protein function in our experimental system. Furthermore, we generate a homology based model of the BamA β-barrel and test our model using insertion mutagenesis, deletion analysis and immunofluorescence to identify β-strands, periplasmic turns and extracellular loops. We show that the surface-exposed loops of the BamA β-barrel are essential.

Details

Original languageEnglish
Article numbere84512
JournalPLoS ONE
Volume8
Issue number12
Publication statusPublished - 23 Dec 2013