The accumulation of misfolded porins in the periplasm of bacteria triggers a proteolytic cascade, initiated by activation of DegS, a member of the family of HtrA proteases. Activation of DegS ultimately leads to the expression of genes encoding the periplasmic protein folding machinery. A new study now reveals that binding of exposed C-termini of unassembled porins to the PDZ domain of DegS ind...

Abstract Background Although Escherichia coli has been widely used for the expression of exogenous proteins, secretory in this system is still a big obstacle. As one most important secretion pathways, hemolysin A (HlyA) E. can transport substrates directly from cytoplasm to extracellular medium without formation any periplasmic intermediate, making it an ideal candidate development production p...

Capsule gene (cps) expression, which normally occurs at low levels in Escherichia coli lon+ cells, increased 38-fold in lon+ cells carrying a Tn10::delta kan insertion mapping to 24 min on the E. coli chromosome. Null mutations in rcsA, rcsB, or rcsC abolished the effect of the Tn10::delta kan insertion. Sequencing of both sides of the Tn10::delta kan insertion localized the insertion to the pr...

In Gram-negative bacteria, lipid modification of proteins is catalysed in a three-step pathway. Apolipoprotein N-acyl transferase (Lnt) catalyses the third step in this pathway, whereby it transfers an acyl chain from a phospholipid to the amine group of the N-terminal cysteine residue of the apolipoprotein. Here, we report the 2.6-Å crystal structure of Escherichia coli Lnt. This enzyme contai...

The cell envelope of gram-negative bacteria includes inner and outer membranes with the periplasmic space in between. The transport systems for many nutrients in these organisms include components in both the periplasm and the inner membrane. In some cases, e.g., maltose, transport components in the outer membrane are also involved. The scope of this review will be limited to a progress report ...

Calcium everywhere The structure of S100B complexed with the p53 peptide provides the first glimpse of how an EF-hand protein recognizes a transcription factor in order to regulate transcriptional activity. Other examples of EF-hand proteins involving transcription regulation include the down-stream regulatory element antagonist modulator DREAM, which functions as a Ca2+dependent DNA-binding tr...

A total of 103 strains of Aeromonas spp. isolated from clinical and from environmental samples was compared by using SDS-PAGE of periplasmic proteins patterns. Strains isolated from Polish children suffering from gastroenteritis did not appear similar to strains isolated from human living in Hong-Kong. Aeromonas sp. strains did not show a tendency to cluster according to their origin. Our resul...

conclusions reteplase was expressed in e. coli top 10 after activation of pbad/giiia promoter region by arabinose and optimized. results the obtained recombinant plasmid was sequenced to confirm the presence and correct framing of reteplase gene regarding the expression of reteplase. maximum production of this enzyme was obtained under the following condition: 0.0002% l-arabinose at 37°c for 2 ...

Expression of eukaryotic proteins in E. coli often results in their aggregation. Proper folding and solubility of therapeutical proteins are the pre-requisite for their bioactivity. This is not achieved in cytoplasmic expression in E. coli because of the absence of disulfide bonds formation. A novel expression/secretion vector was constructed which exploited β-lactamase signal sequence to trans...