title: Sensitive bondforce measurements of ligand-receptor pairs with magnetic beads.
abstract: The bondforces between biotinylated surfaces and streptavidin or avidin coated beads are investigated by a magnetic field based manipulation system for magnetic microbeads. The magnetic field is generated by currents through a set of conducting lines, and its gradient exerts a force onto the magnetic beads. The force can be increased until the bond between the bead and the surface breaks. Consistent with other groups we found two conformations for both investigated bonds. The measured bondforces for the two conformations are for Streptavidin-Biotin: 55.9 and 244.7 fN and for Avidin-Biotin: 15.9 and 58.4 fN. These very low bondforces (10-100 times smaller than earlier measurements) match to the extremely low loading rate of about 1 fN/s. This new technique thus allows to investigate biomolecular bonds by extremely low forces.
authors.affiliation: University of Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany. Michael.Panhorst@Physik.Uni-Bielefeld.DE
authors.forename: Michael
authors.initials: M
authors.lastname: Panhorst
authors.forename: Paul-Bertram
authors.initials: PB
authors.lastname: Kamp
authors.forename: Günter
authors.initials: G
authors.lastname: Reiss
authors.forename: Hubert
authors.initials: H
authors.lastname: Brückl
mesh_terms: D001360:Avidin / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure; D001665:Binding Sites; D001710:Biotin / Q000032:analysis / Q000737:chemistry*; D008280:Magnetics; D008846:Micromanipulation / Q000295:instrumentation / Q000379:methods*; D008863:Microspheres; D010812:Physical Stimulation / Q000295:instrumentation / Q000379:methods; D011485:Protein Binding; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019809:Streptavidin / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure; D013314:Stress, Mechanical
chemical_list: D001360:Avidin; D001710:Biotin; D019809:Streptavidin