Fine-Tuning of σ^E Activation Suppresses Multiple Assembly-Defective Mutations in Escherichia coli.

ABSTRACT: The Gram-negative outer membrane (OM) is a selectively permeable asymmetric bilayer that allows vital nutrients to diffuse into the cell but prevents toxins and hydrophobic molecules from entering. Functionally and structurally diverse β-barrel outer membrane proteins (OMPs) build and maintain the permeability barrier, making the assembly of OMPs crucial for cell viability. In this work, we characterize an assembly-defective mutant of the maltoporin LamB, LamB^G439D We show that the folding defect of LamB^G439D results in an accumulation of unfolded substrate that is toxic to the cell when the periplasmic protease DegP is removed. Selection for suppressors of this toxicity identified the novel mutant degS_A323E allele. The mutant DegS^A323E pr

SUBMITTER: Hart EM 

PROVIDER: S-EPMC6509652 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature