Adherence of Gram-positive bacteria to fibronectin /
Most infections are initiated by microbial adherence to host tissues. Binding of bacteria to fibronectin appears to be a common mechanism of tissue adherence of Gram-positive bacteria. This dissertation presents a molecular characterization of the interaction between fibronectin and fibronectin-bi...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1996.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=739364371&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Most infections are initiated by microbial adherence to host tissues. Binding of bacteria to fibronectin appears to be a common mechanism of tissue adherence of Gram-positive bacteria. This dissertation presents a molecular characterization of the interaction between fibronectin and fibronectin-binding MSCRAMMs from Staphylococcus aureus, Streptococcus dysgalactiae and Streptococcus pyogenes. The primary ligand binding sites of the four fibronectin-binding MSCRAMMs FnbpA (S. aureus), FnbA and FnbB (S. dysgalactiae), and Sfb (S. pyogenes) consist of 35-42 amino acid long motifs repeated 3-5 times. Fibronectin interacts with these motifs through its amino-terminal region comprised of five type I modules. Recombinant proteins containing the fibronectin- binding motifs of the MSCRAMMs bind fibronectin with the Kd values of 3-16 nM as measured using a BlAcore biosensor. A monoclonal antibody was isolated which was specific for the ligand-binding site of FnbA completed with Fri. This antibody enhanced the binding of recombinant FnbA fragments to Fibronectin up to 500 fold. Furthermore, the antibody did not recognize the antigen by itself, and fibronectin was required for the immunological interaction between the antibody and the epitope. Furthermore, the circular dichroism and gel filtration data show an extensive structural transition in the recombinant MSCRAMM fragments upon binding to the ligand. From the above observations, it is concluded that the ligand-binding sites of the MSCRAMMs lack a secondary structure in the absence of fibronectin, but assume an organized structure on ligand binding. Maltose-binding fusion proteins containing pairs of fibronectin type I modules were produced and tested for binding to repeat motifs of the four MSCRAMMs using Western affinity blotting, fluorescence polarization, and BlAcore analysis. Most of the recombinant or synthetic fragments bound to specific sets of type I modules, suggesting that individual repeat motifs bind specific pairs of type I modules of Fn. |
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| Item Description: | Vita. "Major Subject: Biochemistry". |
| Physical Description: | x, 136 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 121-133. |