Two precursors of the heat‐stable enterotoxin of <i>Escherichia coli</i>: evidence of extracellular processing

Rasheed, J. Kamile; Guzman-Verduzco, L M; Kupersztoch, Yankel M.

doi:10.1111/j.1365-2958.1990.tb00593.x

Cited by 51 publications

(53 citation statements)

References 46 publications

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“…Further processing occurs in the periplasmic space or during the crossing of the outer membrane to produce the active 18 (STaP) or 19 (STaH) amino-acid toxins with three disulfide bonds (Rasheed et al, 1990;Sears and Kaper, 1996). The receptor of both STa is a transmembrane glycoprotein with guanylate cyclase activity (guanylyl cyclase C) of the intracytoplasmic domain, that is present at the height of the microvilli of the enterocytes (Nataro and Kaper, 1998;Nagy and Fekete, 1999;Kaper et al, 2004;Gyles and Fairbrother, 2010).…”

Section: The Oligopeptide Toxinsmentioning

confidence: 99%

Escherichia coli virulence factors

Mainil

2013

Veterinary Immunology and Immunopathology

122

104

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a b s t r a c t Escherichia coli was described in 1885 by a German pediatrician, Theodor Escherich, in the faeces of a child suffering diarrhoea. In 1893, a Danish veterinarian postulated that the E. coli species comprises different strains, some being pathogens, others not. Today the E. coli species is subdivided into several pathogenic strains causing different intestinal, urinary tract or internal infections and pathologies, in animal species and in humans. Since this congress topic is the interaction between E. coli and the mucosal immune system, the purpose of this manuscript is to present different classes of adhesins (fimbrial adhesins, afimbrial adhesins and outer membrane proteins), the type 3 secretion system, and some toxins (oligopeptide, AB, and RTX pore-forming toxins) produced by E. coli, that can directly interact with the epithelial cells of the intestinal, respiratory and urinary tracts.

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Section: The Oligopeptide Toxinsmentioning

confidence: 99%

Escherichia coli virulence factors

Mainil

2013

Veterinary Immunology and Immunopathology

122

104

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“…Mature STb is a 48-amino acid peptide, with four Cys residues and no homology to STa (Dreyfus et al, 1992). The inferred N-terminus of pro-STb (residues 1-23) has characteristics of a signal sequence that is cleaved, presumably by a signal peptidase, during export to the periplasm, and the periplasmic STb is then translocated to the extracellular medium (Kupersztoch et al, 1990). We have demonstrated that export of STb to the periplasm requires both SecA and electrochemi-cal potential (Kupersztoch et al, 1990).…”

mentioning

confidence: 99%

“…The inferred N-terminus of pro-STb (residues 1-23) has characteristics of a signal sequence that is cleaved, presumably by a signal peptidase, during export to the periplasm, and the periplasmic STb is then translocated to the extracellular medium (Kupersztoch et al, 1990). We have demonstrated that export of STb to the periplasm requires both SecA and electrochemi-cal potential (Kupersztoch et al, 1990). STa interacts with an enterocyte receptor that activates guanylate cyclase, which, in turn, leads to an increased intestinal secretion (Field et al, 1978;Guerrant et al, 1980).…”

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confidence: 99%

“…Disulfide bridges appear to play a central role in stabilizing the toxin against proteolytic cleavage in the periplasm and also in determining the biological activity of the extracellular STb. There is evidence to suggest that disulfide bond formation is a periplasmic event (Kupersztoch et al, 1990). Mutants that lack disulfides are more susceptible to periplasmic proteolysis than is wild-type toxin (Dreyfus et al, 1992).…”

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confidence: 99%

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The structure ofEscherichia coliheat-stable enterotoxin b by nuclear magnetic resonance and circular dichroism

Sarojadevi

Rizo²,

Wall

et al. 1995

Protein Sci.

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The heat-stable enterotoxin b (STb) is secreted by enterotoxigenic Escherichia coli that cause secretory diarrhea in animals and humans. It is a 48-amino acid peptide containing two disulfide bridges, between residues I O and 48 and 21 and 36, which are crucial for its biological activity. Here, we report the solution structure of STb determined by two-and three-dimensional NMR methods. Approximate interproton distances derived from NOE data were used to construct structures of STb using distance-geometry and simulated annealing procedures. The NMRderived structure shows that STb is helical between residues 10 and 22 and residues 38 and 44. The helical structure in the region 10-22 is amphipathic and exposes several polar residues to the solvent, some of which have been shown to be important in determining the toxicity of STb. The hydrophobic residues on the opposite face of this helix make contacts with the hydrophobic residues of the C-terminal helix. The loop region between residues 21 and 36 has another cluster of hydrophobic residues and exposes Arg 29 and Asp 30, which have been shown to be important for intestinal secretory activity. CD studies show that reduction of disulfide bridges results in a dramatic loss of structure, which correlates with loss of function. Reduced STb adopts a predominantly random-coil conformation. Chromatographic measurements of concentrations of native, fully reduced, and single-disulfide species in equilibrium mixtures of STb in redox buffers indicate that the formation of the two disulfide bonds in STb is only moderately cooperative. Similar measurements in the presence of 8 M urea suggest that the native secondary structure significantly stabilizes the disulfide bonds.

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“…The characteristic of the precuror is to possess the pro region which is not found in precursors of many bacterial proteins. The precur-sor of STh is also reported to possess the pro region as that of STp (8,23). Futhermore, we found that the deletion of the pro region caused the reduction of enterotoxic activity of the culture supermatant of the strain (21).…”

mentioning

confidence: 54%

Functional Properties of Pro Region of Escherichia coli Heat‐Stable Enterotoxin

Yamanaka

Fuke

Hitotsubashi

et al. 1993

Microbiology and Immunology

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Escherichia coli heat-stable enterotoxin Ip (STp) is synthesized as the 72-amino-acid residue precursor consisting of three regions: pre region (amino acid residues 1 to 19), pro region (amino acid residues 20 to 54), and mature ST (mST) region (amino acid residues 55 to 72). We examined the role of the pro sequence of STp in enterotoxigenicity of a strain by deleting the gene fragment encoding amino acids 22 to 57. This deletion caused a remarkable reduction of its enterotoxic activity of culture supernatant. In order to analyze the sequence responsible for the function of the pro region, two additional deletion mutants were made. The deletion of the sequence covering amino acids 29 to 38, which is conserved in all sequences of ST reported, brought about a significant reduction of enterotoxic activity but the deletion of the non-conserved sequence (amino acids 40 to 53) did not. This result shows that conserved sequence is mainly responsible for the function. Subsequently, to examine the mechanism of action of the pro region, plasmids carrying DNA sequences of hybrid proteins consisting of pre-pro-nuclease, pre-mSTnuclease, pre-pro-mST-nuclease and pre-pro-nuclease-mST were constructed. Amino acid sequence determination and SDS-polyacrylamide gel analysis revealed that these fusion proteins were cleaved between pre sequence and pro sequence during secretion and the cleaved fusion proteins were accumulated in periplasmic space. But the amount of hybrid protein accumulated in the periplasmic space varied among the strains. That is, the amount of the pre-pro-nuclease gene product that accumulated in the periplasmic space was the highest of all fusion gene products. These results indicate that the existence of the mST region strongly interferes with the translocation of the gene product into the periplasmic space and that the pro region functions to guide the mST region into the periplasmic space.

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Two precursors of the heat‐stable enterotoxin of Escherichia coli: evidence of extracellular processing

Cited by 51 publications

References 46 publications

Escherichia coli virulence factors

Escherichia coli virulence factors

The structure ofEscherichia coliheat-stable enterotoxin b by nuclear magnetic resonance and circular dichroism

Functional Properties of Pro Region of Escherichia coli Heat‐Stable Enterotoxin

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