Matrix-binding proteins of Staphylococcus aureus: functional analysis of mutant and hybrid molecules.
Microbiology (Reading)
; 145 ( Pt 9): 2497-2505, 1999 Sep.
Article
in En
| MEDLINE
| ID: mdl-10517602
ABSTRACT
The fibrinogen-binding protein ClfA and the collagen-binding protein Cna are surface-associated adhesins of Staphylococcus aureus. ClfA has a dipeptide repeat region R composed mainly of serine and aspartate residues, more than 40 of which are required along with the 28-residue region W, the LPXTG motif and region M to display the ligand-binding region A on the cell surface in a functional form. Cna has a 61-residue region W and at least one 187-residue region B linking the collagen-binding region A to peptidoglycan. A cna mutant of S. aureus lacking region B was shown to bind collagen at the same level as wild-type Cna+ cells, indicating that region B is not necessary for ligand binding. Furthermore, altering the number of B repeats did not influence the level of collagen binding. In order to study the ability of C-terminal domains of Cna and ClfA to support functional ligand-binding activity of different adhesins, chimeric proteins were constructed and expressed in S. aureus. Surprisingly, the presence of a single Cna B domain and a nonapeptide linker located between ClfA region A and Cna region WM failed to support fibrinogen binding by S. aureus cells, despite the fact that ClfA region A was detected on the bacterial surface by immunoblotting. In contrast, the ClfA region A-Cna region B hybrid expressed as a recombinant protein in Escherichia coli did bind fibrinogen in Western ligand blots and in an ELISA-type assay. It is concluded that Cna region B cannot support functional display of ClfA region A on the bacterial cell surface. However, the ClfA dipeptide repeat region R and region WM did promote functional surface expression of the Cna collagen-binding domain in a hybrid Cna-ClfA protein.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Staphylococcus aureus
/
Bacterial Proteins
/
Fibrinogen
/
Adhesins, Bacterial
Language:
En
Journal:
Microbiology (Reading)
Journal subject:
MICROBIOLOGIA
Year:
1999
Document type:
Article