Various creatures live in the deep sea, where pressure could be up to 1000 bar. Thus, hydrostatic pressure is a mild but important factor to biological molecules and can be regarded as a means of modulating protein functions. Here, we report a development of a home-built high-pressure system providing hydrostatic pressure up to 4000 bar. Using the developed technique, we show that the apoptotic activity of BAX protein can be modulated. Importantly, this high-pressure system allows one to investigate the existence of low-lying states of a protein that are not easily accessible at atmospheric pressure.

The development of high-pressure pulsed/cw ESR system was first reported in a PNAS paper published in 2014. Our development of a modified high-pressure system, with a publication in 2017 PCCP, was the second one in the literature. The setup of our high-pressure is similar to what was reported in the 2014 PNAS article, with many small components slightly altered when locally fabricated in Taiwan. Another breakthrough of our study lies in that we demonstrated the use of high-pressure device in modulating protein apoptotic activity. This study suggests an approach to mediate apoptosis. The developed pressure-varying approach is potentially useful for investigating low-lying states of a protein.

This technique utilizes liquid as the pressure transmission material instead of gas. This strategy reduces dangers of handling and storing gas. With this, industries do not need to build gas tanks and safety equipment for handling gas, leading to costs saving. Our research validated the scale-up of the system from microliter to a hundred microliter. Thus, the system can be easily scaled-up to milliliter or liter scales. The high-pressure system could be also helpful for food and biomedical industries. This high-pressure system allows one to investigate the existence of low-lying states of a protein that are not easily accessible at atmospheric pressure. The study of low-lying states of a protein is a key topic in protein-based medicine.