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  5. In-situ observation of growth mechanisms of protein crystals and their perfection under microgravity
2021.02.22
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[Nano Step]
In-situ observation of growth mechanisms of protein crystals and their perfection under microgravity

  • Physical Science
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ISS Science for Everyone

SCIENCE OBJECTIVES FOR EVERYONE

The In-situ Observation of Growth Mechanisms of Protein Crystals and their Perfection under Microgravity (NanoStep) investigation aims to clarify the relationship between crystal growth mechanism, surface morphology, and the perfection of crystals. Crystallization of proteins in microgravity yields crystals with better perfection than crystallization on Earth. The reason for this phenomenon has not been explained from a viewpoint of crystal growth mechanism.

SCIENCE RESULTS FOR EVERYONE

Laser interferometers have for the fist time been employed in ISS to measure the growth rate of lysozyme crystals versus the driving force, supersaturation of solution to investigate the difference of crystal growth mechanisms in gravity and under microgravity. The NanoStep experiment revealed that space grown lysozyme crystals grow faster (!) than the Earth-grown crystals by 30-50%. This result completely conflicts with a preexisting assumption; “space-grown crystals are better because they grow slower under convection-free environment.” This faster growth in space was kinetically analyzed due self-purification of impurities during growth coupled with a reduction of an impurity mediated crystal growth mechanism.

Experiment Description

RESEARCH OVERVIEW

  • It has been emphasized in the literature that the protein crystal perfection increases in microgravity conditions. However, the precise mechanism responsible for such observation is yet to be understood from a fundamental point of view.
  • The objective is to study the correlation of growth mechanisms at various levels of supersaturation and defects induced during growth.
  • Lysozyme is used as a model protein and the growth of the crystal surfaces is observed using a Michelson interferometer.

Media Gallery

NASA Image: ISS033E007364 - Close-up view of the Nano Step payload Specimen Cell prior to insertion into the SCOF (Solution Crystallization Observation Facility) in the Japanese Experiment Module (JEM).
NASA Image: ISS033E007362 Japan Aerospace Exploration Agency astronaut Aki Hoshide,Expedition 33 flight engineer,services the Nano Step payload in the Japanese Experiment Module (JEM).
NASA Image: ISS033E007383 - Close-up view of the Nano Step payload Specimen Cell to be located in the SCOF (Solution Crystallization Observation Facility).

Applications

SPACE APPLICATIONS

This experiment will increase the efficiency of PCG experiments in microgravity.

EARTH APPLICATIONS

The understanding of crystal growth mechanisms will increase the perfection of various crystals and benefit the people on earth.

Operations

OPERATIONAL REQUIREMENTS AND PROTOCOLS

There are 3 samples with different concentrations. The experiment duration for one sample is 35 days. The crystal growth will be observed realtime by Michelson interferometry. The sample will not return.

Install the NanoStep Cell to SCOF, Ryutai Rack. When one sample observation is finished, then the sample will be exchanged by the crew member.

Publications

For more information

PRINCIPAL INVESTIGATOR(S)

TSUKAMOTO Katsuo [Tohoku University]

JAXA’s Utilization Themes List

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