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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2001-7-9
pubmed:abstractText
Binding of human plasminogen to Streptococcus pneumoniae and its subsequent activation promotes penetration of bacteria through reconstituted basement membranes. In this study, we have characterized a novel pneumococcal surface protein with a molecular mass of 47 kDa, designated Eno, which specifically binds human plasmin(ogen), exhibits alpha-enolase activity and is necessary for viability. Using enzyme assays, we have confirmed the alpha-enolase activity of both pneumococcal surface-displayed Eno and purified recombinant Eno protein. Immunoelectron microscopy indicated the presence of Eno in the cytoplasm as well as on the surface of encapsulated and unencapsulated pneumococci. Plasminogen-binding activity was demonstrated with whole pneumococcal cells and purified Eno protein. Binding of activated plasminogen was also shown for Eno; however, the affinity for plasmin is significantly reduced compared with plasminogen. Results from competitive inhibition assays indicate that binding is mediated through the lysine binding sites in plasmin(ogen). Carboxypeptidase B treatment and amino acid substitutions of the C-terminal lysyl residues of Eno indicated that the C-terminal lysine is pivotal for plasmin(ogen)-binding activity. Eno is ubiquitously distributed among pneumococcal serotypes, and binding experiments suggested the reassociation of secreted Eno to the bacterial cell surface. The reassociation was also confirmed by immunoelectron microscopy. The results suggest a mechanism of plasminogen activation for human pathogens that might contribute to their virulence potential in invasive infectious processes.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0950-382X
pubmed:author
pubmed:issnType
Print
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1273-87
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:11442827-Amino Acid Sequence, pubmed-meshheading:11442827-Bacterial Outer Membrane Proteins, pubmed-meshheading:11442827-Carboxypeptidase B, pubmed-meshheading:11442827-Carboxypeptidases, pubmed-meshheading:11442827-Cell Membrane, pubmed-meshheading:11442827-Cell Survival, pubmed-meshheading:11442827-Cross Reactions, pubmed-meshheading:11442827-Cytoplasm, pubmed-meshheading:11442827-Fibrinolysin, pubmed-meshheading:11442827-Gene Expression Regulation, Bacterial, pubmed-meshheading:11442827-Humans, pubmed-meshheading:11442827-Lysine, pubmed-meshheading:11442827-Molecular Sequence Data, pubmed-meshheading:11442827-Mutagenesis, Site-Directed, pubmed-meshheading:11442827-Phosphopyruvate Hydratase, pubmed-meshheading:11442827-Plasminogen, pubmed-meshheading:11442827-Sequence Analysis, Protein, pubmed-meshheading:11442827-Serotyping, pubmed-meshheading:11442827-Streptococcus pneumoniae, pubmed-meshheading:11442827-Streptococcus pyogenes
pubmed:year
2001
pubmed:articleTitle
alpha-Enolase of Streptococcus pneumoniae is a plasmin(ogen)-binding protein displayed on the bacterial cell surface.
pubmed:affiliation
Department of Microbial Pathogenicity, GBF-German Research Centre for Biotechnology, Mascheroder Weg 1, D-38124 Braunschweig, Germany.
pubmed:publicationType
Journal Article