TolC is a multifunctional outer membrane protein of Escherichia coli that folds into a novel alpha-beta-barrel conformation absent in the other model outer membrane proteins used in assembly studies. The data presented in this work show that the unique folded structure of TolC reflects a unique assembly pathway. During its assembly, the newly translocated nascent TolC monomers are released in t...

Chaperones facilitate correct folding of newly synthesized proteins. We show here that the periplasmic FkpA chaperone is required for killing Escherichia coli by colicin M entering cells from the outside. Highly active colicin M preparations were inactive against fkpA mutant cells; 10(4)-fold dilutions killed fkpA(+) cells. Three previously isolated spontaneous mutants tolerant to colicin M car...

BACKGROUND Animal neurotoxin peptides are valuable probes for investigating ion channel structure/function relationships and represent lead compounds for novel therapeutics and insecticides. However, misfolding and aggregation are common outcomes when toxins containing multiple disulfides are expressed in bacteria. METHODS The β-scorpion peptide toxin Bj-xtrIT from Hottentotta judaica and fou...

Gram-negative bacteria are equipped with quality-control systems for the outer membrane (OM) that sense and cope with defective biogenesis of its components. Accumulation of misfolded outer membrane proteins (OMPs) in Escherichia coli leads to activation of σ(E), an essential alternative σ factor that up-regulates transcription of multiple genes required to preserve OM structure and function. D...

Peptidyl isomerases (PPIs) catalyze the backbone trans to cis interconversion of AA–Pro (AA: amino acid residue that precedes Pro) bonds. This reaction is particularly important for folding proteins since only proper cis-Pro configuration at certain (rather rare) key positions allows for attaining the native and thus functional three-dimensional structure. While some PPIs, such as FKBP12, recog...

Historic buildings still perform their role today by being utilized either for original purpose or a new which they are adapted. These have specific requirements that inhabitants must follow. and relating uses maintenance procedures result from adaptive reuse decisions, may not be the most optimal scenario. The imperative is historic used in manner that, on one hand, does endanger value related...