The gain-of-function allele <i>bamA</i><sub><i>E470K</i></sub> bypasses the essential requirement for BamD in β-barrel outer membrane protein assembly.
basic_science · Level V
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- Record sourced from PubMed, PMID 32675245.
- Also identified by DOI 10.1073/pnas.2007696117 and PMC identifier 7414184.
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Abstract
The outer membrane (OM) of gram-negative bacteria confers innate resistance to toxins and antibiotics. Integral β-barrel outer membrane proteins (OMPs) function to establish and maintain the selective permeability of the OM. OMPs are assembled into the OM by the β-barrel assembly machine (BAM), which is composed of one OMP-BamA-and four lipoproteins-BamB, C, D, and E. BamB, C, and E can be removed individually with only minor effects on barrier function; however, depletion of either BamA or BamD causes a global defect in OMP assembly and results in cell death. We have identified a gain-of-function mutation, <i>bamA</i><sub><i>E470K</i></sub> , that bypasses the requirement for BamD. Although <i>bamD</i>::kan <i>bamA</i><sub><i>E470K</i></sub> cells exhibit growth and OM barrier defects, they assemble OMPs with surprising robustness. Our results demonstrate that BamD does not play a catalytic role in OMP assembly, but rather functions to regulate the activity of BamA.
Medical subject headings
- Bacterial Outer Membrane
- Bacterial Outer Membrane Proteins
- Escherichia coli Proteins
- Gain of Function Mutation