Multicomponent efflux complexes constitute a primary mechanism for Gram-negative bacteria to expel toxic molecules for survival. As these complexes traverse the periplasm and link inner and outer membranes, it remains unclear how they operate efficiently without compromising periplasmic plasticity. Combining single-molecule superresolution imaging and genetic engineering, we study in living Esc...

The 5'-nucleotidase of Escherichia coli was shown to be located at the cell wall surface by histochemical techniques utilizing the deposition of inorganic phosphate. Penetration of the 5'-nucleotidase in the periplasmic space was seen only in cells treated with ethylenediaminetetraacetic acid (EDTA)-tris(hydroxymethyl)aminomethane (Tris). The 3'-nucleotidase of E. coli was also found to have a ...

The influence of different carbon and nitrogen sources on growth of recombinant Escherichia coli and human interferon-α2b (IFN-α2b) production in periplasmic space was studied in shake flask culture. A statistical method based on Plackett-Burman design was used to screen the main medium components that greatly influenced the performance of the fermentation process. The optimization of medium wa...

Oxidation of cysteine pairs to disulfide requires cellular factors present in the bacterial periplasmic space. DsbB is an E. coli membrane protein that oxidizes DsbA, a periplasmic dithiol oxidase. To gain insight into disulfide bond formation, we determined the crystal structure of the DsbB-DsbA complex at 3.7 A resolution. The structure of DsbB revealed four transmembrane helices and one shor...

Tripartite multidrug efflux systems of Gram-negative bacteria are composed of an inner membrane transporter, an outer membrane channel and a periplasmic adaptor protein. They are assumed to form ducts inside the periplasm facilitating drug exit across the outer membrane. Here we present the reconstitution of native Pseudomonas aeruginosa MexAB-OprM and Escherichia coli AcrAB-TolC tripartite Res...

Maltose-binding protein (MBP), a member of the periplasmic binding protein family of Gram negative bacteria, is a versatile substrate for protein engineering. In common with other periplasmic proteins, it is extremely protease resistant, and it can fold properly in both the cytoplasmic and periplasmic compartments. It binds a variety of glucose-14-glucose polysaccharides, from maltose and lon...

The structure of the water-soluble, periplasmic domain of the fumarate sensor DcuS (DcuS-pd) has been determined by NMR spectroscopy in solution. DcuS is a prototype for a sensory histidine kinase with transmembrane signal transfer. DcuS belongs to the CitA family of sensors that are specific for sensing di- and tricarboxylates. The periplasmic domain is folded autonomously and shows helices at...

Periplasmic substrate binding proteins (PSBPs) are essential components of the bacterial periplasmic transport system, which transports a wide variety of nutrients from the periplasmic space to the cytoplasm. The glutamate/aspartate binding protein SfGlu/AspBP is a unique PSBP consisting of 279 amino acid residues. The SfGlu/AspBP gene was cloned, over-expressed, and purified by immobilized met...

Pseudomonas aeruginosa cytotoxin has been isolated previously from cell autolysates. Both purified cytotoxin and periplasmic contents (osmotic shock fluid) cross-reacted on Western immunoblots with antibodies specific for cytotoxin. In addition, both preparations caused a significant reduction in antibody-mediated phagocytosis of P. aeruginosa M2 by mouse macrophage cell line P388D1. Phagocytos...

In BtuB, the Escherichia coli TonB-dependent transporter for vitamin B12, substrate binding to the extracellular surface unfolds a conserved energy coupling motif termed the Ton box into the periplasm. This transmembrane signaling event facilitates an interaction between BtuB and the inner-membrane protein TonB. In this study, continuous-wave and pulse electron paramagnetic resonance in a nativ...