Nanoscale mapping and functional analysis of individual adhesins on living bacteria.
Although much progress has been made in the identification and characterization of adhesins borne by pathogenic bacteria, the molecular details underlying their interaction with host receptors remain largely unknown owing to the lack of appropriate probing techniques. Here we report a method, based on atomic force microscopy (AFM) with tips bearing biologically active molecules, for measuring the specific binding forces of individual adhesins and for mapping their distribution on the surface of living bacteria. First, we determined the adhesion forces between the heparin-binding haemagglutinin adhesin (HBHA) produced by Mycobacterium tuberculosis and heparin, used as a model sulphated glycoconjugate receptor. Both the adhesion frequency and adhesion force increased with contact time, indicating that the HBHA-heparin complex is formed via multiple intermolecular bridges. We then mapped the distribution of single HBHA molecules on the surface of living mycobacteria and found that the adhesin is not randomly distributed over the mycobacterial surface, but concentrated into nanodomains.
Unité de Chimie des Interfaces, Université Catholique de Louvain, Croix du Sud 2/18, B-1348 Louvain-la-Neuve, Belgium.
Vincent
V
Dupres
Franco D
FD
Menozzi
Camille
C
Locht
Brian H
BH
Clare
Nicholas L
NL
Abbott
Stéphane
S
Cuenot
Coralie
C
Bompard
Dominique
D
Raze
Yves F
YF
Dufrêne
D018829:Adhesins, Bacterial / Q000737:chemistry / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D006493:Heparin / Q000737:chemistry / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D008846:Micromanipulation / Q000379:methods*; D018625:Microscopy, Atomic Force / Q000379:methods*; D009169:Mycobacterium tuberculosis / Q000378:metabolism*; D036103:Nanotechnology / Q000379:methods*; D011485:Protein Binding; D025941:Protein Interaction Mapping / Q000379:methods*; D013314:Stress, Mechanical
D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; C440647:HbhA protein, Mycobacterium tuberculosis; D008565:Membrane Proteins; D006493:Heparin