scholarly journals The effect of toluidine blue on the survival, dormancy and outer membrane porin proteins (OmpC and OmpF) of Salmonella typhimurium LT2 in seawater

2002 ◽  
Vol 92 (6) ◽  
pp. 1097-1104 ◽  
Author(s):  
R. Ozkanca ◽  
N. Sahin ◽  
K. Isik ◽  
E. Kariptas ◽  
K.P. Flint
Keyword(s):  
Salmonella Typhimurium ◽  
Outer Membrane ◽  
Toluidine Blue ◽  
Outer Membrane Porin ◽  
Porin Proteins

scholarly journals SecY-mediated quality control prevents the translocation of non-gated porins

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sebastian Jung ◽  
Verian Bader ◽  
Ana Natriashvili ◽  
Hans-Georg Koch ◽  
Konstanze F. Winklhofer ◽  
...  
Keyword(s):  
Quality Control ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Channel Activity ◽  
Peptide Cleavage ◽  
E Coli ◽  
Charged Amino Acids ◽  
Proof Reading ◽  
Outer Membrane Porin ◽  
Porin Proteins

Abstract OmpC and OmpF are among the most abundant outer membrane proteins in E. coli and serve as hydrophilic channels to mediate uptake of small molecules including antibiotics. Influx selectivity is controlled by the so-called constriction zone or eyelet of the channel. Mutations in the loop domain forming the eyelet can disrupt transport selectivity and thereby interfere with bacterial viability. In this study we show that a highly conserved motif of five negatively charged amino acids in the eyelet, which is critical to regulate pore selectivity, is also required for SecY-mediated transport of OmpC and OmpF into the periplasm. Variants with a deleted or mutated motif were expressed in the cytosol and translocation was initiated. However, after signal peptide cleavage, import into the periplasm was aborted and the mutated proteins were redirected to the cytosol. Strikingly, reducing the proof-reading capacity of SecY by introducing the PrlA4 substitutions restored transport of OmpC with a mutated channel domain into the periplasm. Our study identified a SecY-mediated quality control pathway to restrict transport of outer membrane porin proteins with a deregulated channel activity into the periplasm.

Characterization of monoclonal antibodies to the outer membrane protein (OmpD) of Salmonella typhimurium

1992 ◽  
Vol 38 (11) ◽  
pp. 1102-1107 ◽  
Author(s):  
Suresh R. Pai ◽  
Yvonne Upshaw ◽  
Shiva P. Singh
Keyword(s):  
Monoclonal Antibodies ◽  
Membrane Protein ◽  
Salmonella Typhimurium ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Structural Similarity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Western Immunoblotting ◽  
Porin Proteins

A panel of monoclonal antibodies, seven against the trimeric and seven against the monomeric forms to outer membrane protein D (OmpD) of Salmonella typhimurium were produced. The specificities of these monoclonal antibodies for the porin proteins of S. typhimurium and their cross-reactions with Salmonella porins OmpC and OmpF were determined by Western immunoblotting and enzyme-linked immunosorbent assay. We observed that OmpD shared more epitopes and had greater structural similarity with OmpC than with OmpF. Key words: Salmonella typhimurium, outer membrane protein, monoclonal antibody, trimeric, monomeric.

Sign in / Sign up

Export Citation Format

Share Document