Linked Life Data

9723916

Source:http://linkedlifedata.com/resource/pubmed/id/9723916

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1998-12-23
pubmed:abstractText
The 220 kDa Bordetella pertussis filamentous haemagglutinin (FHA) is the major extracellular protein of this organism. It is exported using a signal peptide-dependent pathway, and its secretion depends on one specific outer membrane accessory protein, FhaC. In this work, we have investigated the influence of conformation on the FhaC-mediated secretion of FHA using an 80kDa N-terminal FHA derivative, Fha44. In contrast to many signal peptide-dependent secretory proteins, no soluble periplasmic intermediate of Fha44 could be isolated. In addition, cell-associated Fha44 synthesized in the absence of FhaC did not remain competent for extracellular secretion upon delayed expression of FhaC, indicating that the translocation steps across the cytoplasmic and the outer membrane might be coupled. A chimeric protein, in which the globular B subunit of the cholera toxin, CtxB, was fused at the C-terminus of Fha44, was not secreted in B. pertussis or in Escherichia coli expressing FhaC. The hybrid protein was only secreted when both disulphide bond-forming cysteines of CtxB were replaced by serines or when it was produced in DsbA- E. coli. The Fha44 portion of the secretion-incompetent hybrid protein was partly exposed on the cell surface. These results argue that the Fha44-CtxB hybrid protein transited through the periplasmic space, where disulphide bond formation is specifically catalysed, and that secretion across the outer membrane was initiated. The folded CtxB portion prevented extracellular release of the hybrid, in contrast to the more flexible CtxB domain devoid of cysteines. We propose a secretion model whereby Fha44 transits through the periplasmic space on its way to the cell surface and initiates its translocation through the outer membrane before being released from the cytoplasmic membrane. Coupling of Fha44 translocation across both membranes would delay the acquisition of its folded structure until the protein emerges from the outer membrane. Such a model would be consistent with the extensive intracellular proteolysis of FHA derivatives in B. pertussis.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0950-382X
pubmed:author
pubmed:issnType
Print
pubmed:volume
29
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
763-74
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Evidence that a globular conformation is not compatible with FhaC-mediated secretion of the Bordetella pertussis filamentous haemagglutinin.
pubmed:affiliation
INSERM U447, IBL, Institut Pasteur de Lille, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't