March 26, 2021
Keio University
Tokyo University of Science
Meiji University
A research group, including Assistant Professor Eiji Yamamoto of the Faculty of Science and Technology at Keio University, Associate Professor Takuma Akimoto of the Faculty of Science and Technology at Tokyo University of Science, Associate Professor Adai Mitake of the Faculty of Science and Technology at Meiji University, and Professor Ralf Metzler of the University of Potsdam, has discovered that fluctuations in the magnitude of diffusivity arise from protein structures in a solvent exhibiting long-term correlated fluctuations (1/f fluctuations). They have clarified a relationship that extends the Stokes-Einstein relation, demonstrating that the magnitude of the time-varying diffusion coefficient is inversely proportional to the size of the protein.
Recent studies have reported anomalous diffusion phenomena where the diffusivity of molecules shows significant fluctuations over time, sparking interest in elucidating the physical mechanisms that cannot be explained by classical diffusion theory. This study has demonstrated a physical mechanism whereby fluctuations in the diffusivity of molecules, which constantly and complexly change their shape, are attributed to their effective size. Furthermore, within cells, cellular functions are maintained through the diffusion and interaction of various biomolecules. While changes in protein structure are known to be related to the expression of function, this research has revealed the new significance that time-varying structures also affect the diffusivity of the protein itself.
The results of this research were published in the journal of the American Physical Society, "Physical Review Letters," on March 23, 2021. The findings were also featured in an online magazine hosted by the society.
Please see below for the full press release.