Invited Speakers

Yuji C. SASAKI (The University of Tokyo)

Movie of Laue diffraction from the individual gold nanocrystal which is labelled to single protein.

Title: Protein Motions with X-ray Single Molecule Observations
Author: Yuji C. SASAKI
Affiliation: Department of Advanced Materials Science, The University of Tokyo
Email: ycsasaki[at]k.u-tokyo.ac.jp
URL: http://sasakilab.k.u-tokyo.ac.jp/en/
A movie of Laue diffraction from an individual gold nanocrystal which is labelled to a single protein. Even at 100 kfps, the protein image runs at a very high speed.
In 1998, we have proposed single molecule techniques using short wavelength probes, such as X-rays, electrons, and neutron. In this presentation, I will introduce single molecular dynamics observation techniques that are developed in our lab and discuss possible applications. Diffracted X-Ray Tracking (DXT) using normal synchrotron orbital radiation source has been developed for obtaining the information of the 3D internal motions of single protein molecules with both high time-resolution (nano-seconds or micro-seconds) and high precision (nm/1000). DXT is a method to obtain three-dimensional (3D) dynamics through trajectories of the Laue diffraction spots from the labelled individual gold nanocrystal. This concept can be applied to utilize also with electrons or neutrons. An important point is that these single molecule methods is applied to labelling techniques.
DXT can be used to trace functional motions at single molecule level in two rotational axes, tilting and twisting views. Gold nanocrystal immobilized on a protein is used as tracer for structural changes of the target proteins. Now, in other DXT’s samples, we try to observe the structural fluctuations of intrinsically disordered proteins (IDP), for example, tau proteins in Alzheimer paired helical filaments-like fibers, or alpha-synuclein which is of great interest to Parkinson's researchers. And, we have applied DXT method as a high time resolution (10µs) and high positional accuracy (-pm) detection system for the time-resolved dynamical interactions between a single gold nanocrystal and localized individual super-saturated molecule networks.
Biographical Sketch: Prof. Yuji C. SASAKI is currently studying at the Department of Advanced Materials Science in the University of Tokyo. After receiving his Dc. Engineering degree in Material Sciences from Tohoku University, he worked at Advanced Research Laboratory, Hitachi Ltd. as a Research Scientist from 1991 to 1997. Then, he moved to The Japan Synchrotron Radiation Research Institute/SPring-8 as Senior Scientist. Prof. Sasaki has been studying the methodology of protein dynamics, especially using short wavelength probes, such as X-rays, electrons, and neutron. In 1998, he has proposed new single molecule techniques using short wavelength probes. This method is called Diffracted X-ray Tracking (DXT), which is the first method of the single molecular technique using quantum beam in the world. Currently, He has completed new other single molecule methodologies using electrons (Diffracted Electron Tracking: DET) and neutrons (Diffracted Neutron Tracking: DNT). For his creation of new single molecule techniques using quantum beams, he received the IBM Japan Science Prize in 2007.