The role of the periplasmic -carbonic anhydrase ( -CA) (HP1186) in acid acclimation of Helicobacter pylori was investigated. Urease and urea influx through UreI have been shown to be essential for gastric colonization and for acid survival in vitro. Intrabacterial urease generation of NH3 has a major role in regulation of periplasmic pH and inner membrane potential under acidic conditions, allo...

Most swimming bacteria produce thrust by rotating helical filaments called flagella. Typically, the flagella stick out into the external fluid environment; however, in the spirochetes, a unique group that includes some highly pathogenic species of bacteria, the flagella are internalized, being incased in the periplasmic space; i.e., between the outer membrane and the cell wall. This coupling be...

The periplasmic space of Gram-negative bacteria such as Escherichia coli and Salmone~la typh~murium contains a large variety of proteins with a wide range of functions. These proteins are associated with nutrient metabolism, transport, chemotaxis, antibiotic resistance, and energy utilization. There are about a dozen or so periplasmic proteins that participate in transport of small polar substr...

A remarkable feature of proteins of the SecD and SecF family involved in protein translocation is that they possess a very large first periplasmic domain. Here we report that this large first periplasmic domain is not required for the SecD-SecF interaction but that it is important for catalyzing protein translocation.

Periplasmic aminopeptidase II of yeast was isolated from protoplast supernatants by ammonium sulfate precipitation, DEAE-Sephacel chromatography and affinity chromatography on immobilized bestatin. This isolation method is more rapid than conventional procedures and, in addition, avoids contact of the enzyme with yeast proteinases. Thus the preparation obtained is likely to represent the native...

In Escherichia coli, a family of periplasmic disulfide oxidoreductases catalyzes correct disulfide bond formation in periplasmic and secreted proteins. Despite the importance of native disulfide bonds in the folding and function of many proteins, a systematic investigation of the in vivo substrates of E. coli periplasmic disulfide oxidoreductases, including the well characterized oxidase DsbA, ...

ToxR and ToxS are integral membrane proteins that activate the transcription of virulence genes in Vibrio cholerae. ToxR can be separated into three different domains: an N-terminal cytoplasmic DNA binding domain, a central transmembrane domain, and a C-terminal periplasmic domain. ToxS is thought to enhance ToxR-mediated transcriptional activation through a periplasmic interaction. By P22 chal...

According to x-ray structure, the lactose permease (LacY) is a monomer organized into N- and C-terminal six-helix bundles that form a deep internal cavity open on the cytoplasmic side with a single sugar-binding site at the apex. The periplasmic side of the molecule is closed. During sugar/H(+) symport, a cavity facing the periplasmic side is thought to open with closure of the inward-facing cy...