Dissecting streptavidin-biotin interaction with a laminar flow chamber.
A laminar flow chamber was used to study single molecule interactions between biotinylated surfaces and streptavidin-coated spheres subjected to a hydrodynamic drag lower than a piconewton. Spheres were tracked with 20 ms and 40 nm resolution. They displayed multiple arrests lasting between a few tens of milliseconds and several minutes or more. Analysis of about 500,000 positions revealed that streptavidin-biotin interaction was multiphasic: transient bound states displayed a rupture frequency of 5.3 s(-1) and a rate of transition toward a more stable configuration of 1.3 s(-1). These parameters did not display any significant change when the force exerted on bonds varied between 3.5 and 11 pN. However, the apparent rate of streptavidin-biotin association exhibited about 10-fold decrease when the wall shear rate was increased from 7 to 22 s(-1), which supports the existence of an energy barrier opposing the formation of the transient binding state. It is concluded that a laminar flow chamber can yield new and useful information on the formation of molecular bonds, and especially on the structure of the external part of the energy landscape of ligand-receptor complexes.
Pierres
Anne
A
Laboratoire d'Immunologie, INSERM U 387, Hôpital Ste-Marguerite, BP 29, 13274 Marseille Cedex 09, France.
Touchard
Dominique
D
Benoliel
Anne-Marie
AM
Bongrand
Pierre
P
D000327:Adsorption; D000538:Aluminum Silicates; D001665:Binding Sites; D055592:Biophysical Phenomena; D001703:Biophysics; D001710:Biotin / Q000737:chemistry*; D008024:Ligands; D008863:Microspheres; D012212:Rheology / Q000295:instrumentation; D019809:Streptavidin / Q000737:chemistry*; D013499:Surface Properties
D000538:Aluminum Silicates; D008024:Ligands; D001710:Biotin; D019809:Streptavidin; C011934:mica