Piezoelectric allostery of protein

Advancing piezoelectric 2D nanomaterials for applications in drug delivery systems and therapeutic approaches

Precision drug delivery and multimodal synergistic therapy are crucial in treating diverse ailments, such as cancer, tissue damage, and degenerative diseases. Electrodes that emit electric pulses have proven effective in enhancing molecule release and permeability in drug delivery systems. Moreover, the physiological electrical microenvironment plays a vital role in regulating biological functions and triggering action potentials in neural and muscular tissues. Due to their unique noncentrosymmetric structures, many 2D materials exhibit outstanding piezoelectric performance, generating positive and negative charges under mechanical forces. This ability facilitates precise drug targeting and ensures high stimulus responsiveness, thereby controlling cellular destinies. Additionally, the abundant active sites within piezoelectric 2D materials facilitate efficient catalysis through piezochemical coupling, offering multimodal synergistic therapeutic strategies. However, the full potential of piezoelectric 2D nanomaterials in drug delivery system design remains underexplored due to research gaps. In this context, the current applications of piezoelectric 2D materials in disease management are summarized in this review, and the development of drug delivery systems influenced by these materials is forecast.

Coulombic Organization in Membrane-Embedded Rotary Motor of ATP Synthase

The electrochemical potential difference of protons across the membrane is used to synthesize ATP through the proton-motive rotatory motion of the membrane-embedded region of ATP synthase called F_o. In this study, we illuminate the unsolved proton-motive rotary mechanism of F_o on the basis of atomistic simulation with full description of protein, lipid, and water molecules, and highlight the underlying Coulombic design. We first show that a water channel is spontaneously formed at the interfacial region between the rotor (c-ring) and the stator (a-subunit). The observed water channel is a full channel penetrating the membrane, but a Coulomb barrier by a strictly conserved arginine of the a-subunit dominates at the midpoint of the full channel, preventing proton leakage. Our molecular dynamics simulation further demonstrates that the Coulomb attraction between the arginine and the essential glutamic acid of the c-subunit drives the c-ring rotation. We finally illustrate that the charge-state changes of the glutamic acids, enabled by the electrochemical potential difference of proton and the thermal motion, can produce unidirectional rotation of the c-ring.

Piezoelectric Peptide and Metabolite Materials

Piezoelectric materials are important for many physical and electronic devices. Although many piezoelectric ceramics exhibit good piezoelectricity, they often show poor compatibility with biological systems that limits their biomedical applications. Piezoelectric peptide and metabolite materials benefit from their intrinsic biocompatibility, degradability, and convenient biofunctionalization and are promising candidates for biological and medical applications. Herein, we provide an account of the recent progress of research works on piezoelectric peptide and metabolite materials. This review focuses on the growth mechanism of peptide and metabolite micro- and nanomaterials. The influence of self-assembly processes on their piezoelectricity is discussed. Peptide and metabolite materials demonstrate not only outstanding piezoelectric properties but also unique electronic, optical, and physical properties, enabling their applications in nanogenerators, sensors, and optical waveguiding devices.

Long-range coupling between ATP-binding and lever-arm regions in myosin via dielectric allostery

A protein molecule is a dielectric substance, so the binding of a ligand is expected to induce dielectric response in the protein molecule, considering that ligands are charged or polar in general. We previously reported that binding of adenosine triphosphate (ATP) to molecular motor myosin actually induces such a dielectric response in myosin due to the net negative charge of ATP. By this dielectric response, referred to as "dielectric allostery," spatially separated two regions in myosin, the ATP-binding region and the actin-binding region, are allosterically coupled. In this study, from the statistically stringent analyses of the extensive molecular dynamics simulation data obtained in the ATP-free and the ATP-bound states, we show that there exists the dielectric allostery that transmits the signal of ATP binding toward the distant lever-arm region. The ATP-binding-induced electrostatic potential change observed on the surface of the main domain induced a movement of the converter subdomain from which the lever arm extends. The dielectric response was found to be caused by an underlying large-scale concerted rearrangement of the electrostatic bond network, in which highly conserved charged/polar residues are involved. Our study suggests the importance of the dielectric property for molecular machines in exerting their function.

Keeping the focus on biophysics and actin filaments in Nagoya: A report of the 2016 "now in actin" symposium

Regulatory systems in living cells are highly organized, enabling cells to response to various changes in their environments. Actin polymerization and depolymerization are crucial to establish cytoskeletal networks to maintain muscle contraction, cell motility, cell division, adhesion, organism development and more. To share and promote the biophysical understanding of such mechanisms in living creatures, the "Now in Actin Study: -Motor protein research reaching a new stage-" symposium was organized at Nagoya University, Japan on 12 and 13, December 2016. The organizers invited emeritus professor of Nagoya and Osaka Universities Fumio Oosawa and leading scientists worldwide as keynote speakers, in addition to poster presentations on cell motility studies by many researchers. Studies employing various biophysical, biochemical, cell and molecular biological and mathematical approaches provided the latest understanding of mechanisms of cell motility functions driven by actin, microtubules, actin-binding proteins, and other motor proteins.

Dielectric Allostery of Protein: Response of Myosin to ATP Binding

Protein uses allostery to execute biological function. The physical mechanism underlying the allostery has long been studied, with the focus on the mechanical response by ligand binding. Here, we highlight the electrostatic response, presenting an idea of "dielectric allostery". We conducted molecular dynamics simulations of myosin, a motor protein with allostery, and analyzed the response to ATP binding which is a crucial step in force-generating function, forcing myosin to unbind from the actin filament. We found that the net negative charge of ATP causes a large-scale, anisotropic dielectric response in myosin, altering the electrostatic potential in the distant actin-binding region and accordingly retracting a positively charged actin-binding loop. A large-scale rearrangement of electrostatic bond network was found to occur upon ATP binding. Since proteins are dielectric and ligands are charged/polar in general, the dielectric allostery might underlie a wide spectrum of functions by proteins.