Single-Molecule Force Spectroscopy of Mycobacterial Adhesin-Adhesin Interactions
| Autor: | Yves F. Dufrêne, Camille Locht, Frédérique Dewitte, Dominique Raze, Claire Verbelen |
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| Přispěvatelé: | UCL - AGRO/CABI - Département de chimie appliquée et des bio-industries |
| Rok vydání: | 2007 |
| Předmět: |
Protein Folding
Genomics and Proteomics biology Force spectroscopy Membrane Proteins Hemagglutinin (influenza) Mycobacterium tuberculosis Plasma protein binding Adhesion Microscopy Atomic Force Microbiology Protein Structure Tertiary Bacterial adhesin Protein structure Bacterial Proteins Biochemistry Membrane protein Biophysics biology.protein Protein Interaction Domains and Motifs Protein folding Dimerization Molecular Biology Protein Binding |
| Zdroj: | Journal of bacteriology, Vol. 189, no. 24, p. 8801-6 (2007) |
| ISSN: | 1098-5530 0021-9193 |
| Popis: | The heparin-binding hemagglutinin (HBHA) is one of the few virulence factors identified for Mycobacterium tuberculosis . It is a surface-associated adhesin that expresses a number of different activities, including mycobacterial adhesion to nonphagocytic cells and microbial aggregation. Previous evidence indicated that HBHA is likely to form homodimers or homopolymers via a predicted coiled-coil region located within the N-terminal portion of the molecule. Here, we used single-molecule atomic-force microscopy to measure individual homophilic HBHA-HBHA interaction forces. Force curves recorded between tips and supports derivatized with HBHA proteins exposing their N-terminal domains showed a bimodal distribution of binding forces reflecting the formation of dimers or multimers. Moreover, the binding peaks showed elongation forces that were consistent with the unfolding of α-helical coiled-coil structures. By contrast, force curves obtained for proteins exposing their lysine-rich C-terminal domains showed a broader distribution of binding events, suggesting that they originate primarily from intermolecular electrostatic bridges between cationic and anionic residues rather than from specific coiled-coil interactions. Notably, similar homophilic HBHA-HBHA interactions were demonstrated on live mycobacteria producing HBHA, while they were not observed on an HBHA-deficient mutant. Together with the fact that HBHA mediates bacterial aggregation, these observations suggest that the single homophilic HBHA interactions measured here reflect the formation of multimers that may promote mycobacterial aggregation. |
| Databáze: | OpenAIRE |
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