title: Magnetic tweezers measurement of the bond lifetime-force behavior of the IgG-protein A specific molecular interaction.
abstract: The bond lifetime-force behavior of the immunoglobulin G (IgG)-protein A interaction has been studied with magnetic tweezers to characterize the physical properties of the bond under nonequilibrium conditions. Super-paramagnetic microparticles were developed that have a high and uniform magnetization to simultaneously apply a piconewton-scale tensile force to many thousands of IgG-protein A bonds. A strong and a weak slip bond were detected with an effective bond length that is characteristic of short-range, stiff intermolecular interactions. These bonds are attributed to the interaction of protein A with the constant region (Fc) and heavy chain variable domain (VH) of IgG, respectively. The IgG-VH interaction appears to be one of the weakest specific molecular interactions that has been identified with a single molecule force measurement technique. This study demonstrates that magnetic tweezers can be used to rapidly characterize very weak biomolecular interactions as well as strong biomolecular interactions with a high degree of accuracy.
authors.affiliation: School of Chemical and Biomedical Engineering, Forney Hall, Purdue University, West Lafayette, IN 47907-1283, USA.
authors.forename: Hao
authors.initials: H
authors.lastname: Shang
authors.forename: Gil U
authors.initials: GU
authors.lastname: Lee
mesh_terms: D007074:Immunoglobulin G / Q000737:chemistry* / Q000378:metabolism*; D008280:Magnetics; D046529:Microscopy, Electron, Transmission; D011485:Protein Binding; D013205:Staphylococcal Protein A / Q000737:chemistry* / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D007074:Immunoglobulin G; D013205:Staphylococcal Protein A