Previous N-ethylmaleimide-labeling studies show that ligand binding increases the reactivity of single-Cys mutants located predominantly on the periplasmic side of LacY and decreases reactivity of mutants located for the most part of the cytoplasmic side. Thus, sugar binding appears to induce opening of a periplasmic pathway with closing of the cytoplasmic cavity resulting in alternative access...

background: production of tissue plasminogen activator protein (t-pa) in prokaryotes systems has many problems such as the lack of active protein production, multiple purification steps, and renaturation process which has been shown to be costly and time-consuming. methods: in this study, reteplase which is the nonglycosylated active domain of t-pa was used to transform top10 escherichia coli (...

Efforts to express lipase in the periplasmic space of Escherichia coli have so far been unsuccessful andmost of the expressed recombinant lipases accumulate in the insoluble cell fraction. To evaluate the role ofnative and heterologous signal peptides in translocation of the lipase across the inner membrane of E. coli,the lipase gene (btl2) was cloned downstream of the native ...

Human Interferon β (INF-β) is a member of cytokines family which different studies have shown its immunomodulatory and antiviral activities. In this study an expression vector was designed and constructed for expression of human INF-β-1b either in shake flasks and bench top bioreactor. The designed vector was constructed based upon pET-25b(+) with T7 promoter. Recombinant human beta interferon ...

The periplasm of Gram-negative bacteria is a dynamic and physiologically important subcellular compartment where the constant exposure to potential environmental insults amplifies the need for proper protein folding and modifications. Top-down proteomics analysis of the periplasmic fraction at the intact protein level provides unrestricted characterization and annotation of the periplasmic prot...

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...

The N- and C-terminal six-helix bundles of lactose permease (LacY) form a large internal cavity open on the cytoplasmic side and closed on the periplasmic side with a single sugar-binding site at the apex of the cavity near the middle of the molecule. During sugar/H(+) symport, an outward-facing cavity is thought to open with closing of the inward-facing cavity so that the sugar-binding site is...