Colicin V (ColV) is a peptide antibiotic that kills sensitive cells by disrupting their membrane potential once it gains access to the inner membrane from the periplasmic face. Recently, we constructed a translocation suicide probe, RR-ColV, that is translocated into the periplasm via the TAT pathway and thus kills the host cells. In this study, we obtained an RR-ColV-resistant mutant by using ...

The endonuclease of Bacillus subtilis specific for single-stranded deoxyribonucleic acid is absent in spores, appears during germination only after the start of deoxyribonucleic acid synthesis, and is located almost exclusively in the periplasm.

Dsb proteins (DsbA, DsbB, DsbC, and DsbD) catalyze formation and isomerization of protein disulfide bonds in the periplasm of Escherichia coli. By using a set of Dsb coexpression plasmids constructed recently, we analyzed the effects of Dsb overexpression on production of horseradish peroxidase (HRP) isozyme C that contains complex disulfide bonds and tends to aggregate when produced in E. coli...

Lactose permease (LacY) is the prototype of the major facilitator superfamily (MFS) of secondary transporters. Available structures of LacY reveal a state in which the substrate is exposed to the cytoplasm but is occluded from the periplasm. However, the alternating-access transport mechanism requires the existence of a periplasm-facing state. We recently showed that inverted-topology structura...

The opportunistic pathogen Pseudomonas aeruginosa secretes a capsule-like polysaccharide called alginate that is important for evasion of host defenses, especially during chronic pulmonary disease of patients with cystic fibrosis (CF). Most proteins for alginate biosynthesis are encoded by the 12-gene algD operon. Interestingly, this operon also encodes AlgL, a lyase that degrades alginate. Mut...

Pseudomonas aeruginosa is an opportunistic pathogen of particular significance to cystic fibrosis patients. This bacterium produces the exopolysaccharide alginate, which is an indicator of poor prognosis for these patients. The proteins required for alginate polymerization and secretion are encoded by genes organized in a single operon; however, the existence of internal promoters has been repo...

This report suggests an important physiological role of a CYP in the accumulation of uroporphyrin I arising from catalytic oxidative conversion of uroporphyrinogen I to uroporphyrin I in the periplasm of Escherichia coli cultured in the presence of 5-aminolevulinic acid. A structurally competent Streptomyces griseus CYP105D1 was expressed as an engineered, exportable form in aerobically grown E...

The C4-dicarboxylate sensor kinase DcuS is membrane integral because of the transmembrane (TM) helices TM1 and TM2. Fumarate-induced movement of the helices was probed in vivo by Cys accessibility scanning at the membrane-water interfaces after activation of DcuS by fumarate at the periplasmic binding site. TM1 was inserted with amino acid residues 21-41 in the membrane in both the fumarate-act...

To identify export and sorting information in outer membrane protein PhoE of Escherichia coli K-12, a set of deletions was created, resulting in the removal of N-terminal amino acids of the mature protein. Pulse-chase experiments revealed that some mutant proteins were slowly or not at all processed, but there was not correlation between processing rate and the extent of the deletions. The unpr...