New study focuses on growing enzymes on International Space Station to help develop nerve agent antidotes

The International Space Station’s (ISS) microgravity environment could provide a means of improving the understanding of toxic nerve agents, such as sarin and VX, and how to combat them, according to a researchers from the National Institutes of Health (NIH)-supported Countermeasures Against Chemical Threats (CounterACT) project.

The project centers on the study of organophosphates (OPs), a family chemicals that work to block the enzyme acetylcholinesterase (AChE). AChE is important for the body’s ability to allow muscles to relax after nervous system stimulation. When this enzyme is blocked by OPs such as sarin or VX, muscles cannot relax and the resulting condition leads to paralysis and potential death.

According to NIH, developing antidotes to OP poisoning requires detailed knowledge about the structure of AChE, however, the forces of Earth’s gravity have posed challenges to that area of research. This fact led researchers to send human AChE samples to ISS in June in order to grow large crystals of pure enzyme to a size not achievable on earth due to gravitational interference.

“By taking advantage of the microgravity conditions of the International Space Station, we hope to grow better, more uniform crystals that we are unable to grow on Earth,” Andrey Kovalevsky of the Oak Ridge National Laboratory said.

Once the enzyme crystals grow to a large enough size, the samples will be flown back down to earth to be analyzed via a method called neutron diffraction, which will provide an atomic-level view of the enzymes.

University of California-San Diego (UCSD) researcher Zoran Radić said the technique would enable researchers to get a closer look at how the enzyme interacts with pesticides and nerve agents and learn about how the bond between the two can be chemically reversed.

Contemporary countermeasures to OP exposure work by reactivating AChE by breaking its chemical bond with OP, however, the speed in which they become effective is too slow.

NIH said in a release that the project will help researchers develop antidotes that break the AChE-OP bond more quickly and can be delivered orally, which is key when dealing with large-scale exposure to nerve poisons.

Contributions to the project have been made by the National Institute of Neurological Disorders and Stroke (NINDS), the Oak Ridge National Laboratory, UCSD, the University of Utah, and the NIH Office of the Director.