Cross-species chimeras reveal BamA POTRA and β-barrel domains must be fine-tuned for efficient OMP insertion.

摘要: BAM is a conserved molecular machine, the central component of which BamA. Orthologues BamA are found in all Gram-negative bacteria, chloroplasts and mitochondria where it required for folding insertion β-barrel containing integral outer membrane proteins (OMPs) into membrane. binds unfolded precursors via five polypeptide transport-associated (POTRA) domains at its N-terminus. The C-terminus folds domain, tethers to involved OMP insertion. orthologues bacteria appear function species-specific manner. Here we investigate nature this species-specificity by examining whether chimeric Escherichia coliBamA fusion proteins, carrying either or POTRA from various orthologues, can functionally replace E.coliBamA. We demonstrate that many interchangeable. show defects orthologous be rescued compensatory mutations within β-barrel. These data reveal barrel must precisely aligned ensure efficient