It has been elucidated that ATP can nonspecifically dissolve protein aggregates. We examined the microscopic mechanisms by using atomistic simulations and proposed that ATP adenosines-proteins backbone atom interactions destabilize aggregated protein. This mechanism is worthwhile for verification due to universal nature, while it is difficult to directly test it by conventional approaches due to rare-event nature for simulations with machine power of today. To overcome the computational difficulty, we newly developed simulation techniques to effectively treat multimeric protein disassembly and biochemical reactions within realistic computational time.
Inspired by the structure and dynamic functions of transmembrane proteins, we have developed a series of multiblock molecules having an alternating sequence of hydrophobic and hydrophilic domains. These amphiphilic molecules form unimolecular or supramolecular ion channels in lipid bilayer membranes, with responsiveness to external stimuli, such as osmotic pressure (tension), ligand addition, and electric fields. In addition, the molecules bearing phosphate ester groups allow directional control of molecular alignments in the membranes. This feature has great advantages for future applications in biological, medicinal and materials sciences.
We analyzed the kinetics and thermodynamics of amyloid fibril formation by the amyloidogenic variant of apolipoprotein A-I and α-synuclein based on the Finke-Watzky two-step model of a homogeneous nucleation followed by autocatalytic fibril growth. The results demonstrated that in apoA-I, the nucleation process is enthalpically unfavorable but entropically favorable likely because of the desolvation of hydrophobic regions in the molecule, whereas the nucleation of α-synuclein is enthalpically and entropically unfavorable. Interestingly, Parkinson’s disease-related mutation and C-terminal truncation in α-synuclein were found to decrease the enthalpic barrier for nucleation, thereby promoting autocatalytic nucleation in fibril formation.
The mammalian master circadian clock locates in the suprachiasmatic nucleus (SCN) of the hypothalamus, where ca. 20,000 neurons constitute a hierarchical network. The SCN receives direct light information from the retina, integrates the environmental information, transmits the rhythmic information to other brain areas and peripheral organs in the body, and finally regulates 24 h physiological functions. In the last decade, I have reported circadian Ca2+ rhythms in the SCN network and isolated single SCN neurons, circadian voltage rhythms synchronized in the SCN network, and ultradian Ca2+ rhythms in the primary output regions of the SCN. In this review, I summarize my 10 years of work and discuss the future perspective.