Experiment

Results of Protein Crystal Growth experiment in Kibo (Flash report)

The protein crystals acquired in the High-Quality Protein Crystal Growth (PCG) experiment during Astronaut Kanai's stay on the International Space Station (ISS) were brought back to Earth by the Dragon SpX-14 spacecraft on May 6, 2018. The crystals were handed over to the researchers and are currently undergoing various analyses including data collections at synchrotron facilities such as SPring-8 and Photon Factory. Here is a brief report of a part of the experiment results.

AoMan134A, a protein derived from aspergillus was discovered by the research team headed by Assistant Professor Motoyuki Shimizu from Meijo University. It is a hydrolase, which plays a key part in degrading mannans, polysaccharides found in legume seed and cell wall of softwood. Mannans constitute a part of the common natural biomass, and Ao134A is expected to contribute to industrial utilization of softwood biomass.

The experiment in space of this session has brought about larger crystals of AoMan134A (see photos below). Ground-based experiments only had given the maximum resolution of 2.5Å, while the crystals in this space experiment diffracted up to a 1.5Åresolution. The data helped to determine the precise structure of the AoMan134A for the first time. The team from Meijo University is currently working on mutant enzymes having altered functions. JAXA is determined to provide more results of PCG experiments to academic researchers and institutes of the private sector, hoping to make contributions in this field.

Protein crystals produced in ground-based experiments (Credit: Meijo University/JAXA)	Protein crystal produced in space (Credit: Meijo University/JAXA)

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