title: Dynamical regulations of protein-ligand bindings at single molecular level.
abstract: We present new quantitative regulations of the binding-affinity using dynamical single-molecule detection system with X-rays. In the study of antigen-antibody interactions, we found that structural fluctuations of single-molecules were negatively regulated by antigen-binding. Although strategies to produce ligand-induced stability have been well studied from the macro aspect both theoretically and experimentally, our dynamical single-molecular experimental results are first observations with angstrom accuracy in the real-time and space. It is considered that those negative regulations of protein structural fluctuations with binding event are related to biological functions. In addition, we clarified that ratio between antigen-binding condition and no-binding one in observed structural fluctuations are extremely relative to the binding-affinity. These results indicate that the phenomena of protein-ligand interactions considered as stable states can be defined as results of dynamical processes at the single-molecule level. Such new quantifications from angstrom-level structural fluctuations can be applied to various biological science and biotechnologies.
authors.affiliation: Sasaki-team, Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, 2-20-5, Akebono-cho, Tachikawa, Tokyo 190-0012, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Sagawa
authors.forename: Takachika
authors.initials: T
authors.lastname: Azuma
authors.forename: Yuji C
authors.initials: YC
authors.lastname: Sasaki
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry; D000937:Antigen-Antibody Reactions; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry; D008024:Ligands; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D000911:Antibodies, Monoclonal; D007140:Immunoglobulin Fab Fragments; D008024:Ligands; D011506:Proteins