Commercial Protein Crystal Growth Experiment (CPCG)

Objectives

The objective of this experiment were: (1) to obtain as high quality crystals (T6) of human insulin as possible, (2) to obtain enhanced x-ray diffraction data, and (3) to examine the space-grown crystals with synchrotron radiation.

Shuttle-Mir Missions
STS-86

Approach
The insulin sample was crystallized in large-scale batch mode with temperature change as the means to induce protein crystal growth. The space-flight hardware was the Protein Crystallization Facility (PCF) which had flown on 12 previous missions. The PCF hardware was accommodated in a CRIM that generated the temperature change profile and maintained constant 22 degrees Celsius temperature at the end of the 24 hour temperature gradient. The sample was recombinant human insulin provided by Eli Lilly in conjunction with its collaboration with Hauptman Woodward Medical Institute - Drs. G. David Smith and Robert Blessing.

Results
There was a large difference between the space-grown and Earth-grown crystals with the microgravity crystals exhibiting superior conformation and optical clarity. They were very large, being rhombohedra of 1.5 mm on a side in some cases. The synchrotron x-ray diffraction data showed that the microgravity crystal had increased internal resolution and reduced rocking width, indicative of increased internal molecular order in the space-grown crystals.

The synchrotron data indicate that the space-grown crystals have superior x-ray diffraction characteristics. These crystals provided Hauptman Woodward Medical Research Institute with the first cryotemperature diffraction data and the highest resolution data ever measured of T6 insulin.

Earth Benefits
Results of this new work facilitate a better understanding of the nature of the molecular electrostatic charges which are important when insulin interacts with its receptor and the forces which hold the hexamer together. Enlightment of the insulin and receptor interactions could lead to advances for developing new insulin preparations for improved diabetes therapy.

Publications
None available at this time.

Principal Investigators
Lawrence J. Delucas, O.D., Ph.D.
University of Alabama at Birmingham

Co-Investigators
Dr. Marianna Long
Dr. Robert Blessing
Dr. David Smith

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Page last updated: 07/16/1999

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