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First Protein Crystallization Experiments on The International Space Station: Sweet Success in Space With ThaumatinWe determined the room temperature 1.2 A structure of thaumatin using a crystal grown in the first protein crystallization experiment conducted aboard the International Space Station (ISS). The crystals were grown in the Enhanced Gaseous Nitrogen Dewar (EGN) developed by Alexander McPherson and co-workers. EGN transports frozen solutions contained in tygon tubing in a liquid nitrogen Dewar to ISS where the tubes then thaw. Batch, free interface diffusion (FID), or vapor diffusion crystallization occurs after thawing. EGN was flown to the ISS on STS-106 on September 8, 2000. This was a "risk mitigation" flight that tested EGN performance and the process of conducting experiments on ISS. We focused on how to map a hanging drop crystallization recipe to the EGN FID method. Thaumatin was chosen as the test system. Three series of crystallization recipes were set-up. Each series tested different volume ratios of protein-rich solution to precipitant-rich solution. The series differed from each other by fixing either the protein concentration or the amount of protein in the solutions. Upon return of the samples to Earth on October 24 by STS-92, bubbles that spanned the diameter of the tubing were observed in all tubes. Such bubbles interrupt liquid-liquid diffusion and force vapor diffusion equilibration to occur instead. Nonetheless, crystals grew in 9 of 30 tubes. Many large crystals were grown, the largest being 2.0 x 1.1 x 1.0 cubic mm. The largest crystal was used to collect data at room temperature on beamline 7-1 of the Stanford Synchrotron Radiation Source to a maximum resolution of 1.2 A. The structure was refined anisotropically using SHELX with a data to parameter ratio of 4.5 to give an R(sub factor) of 15.8% (R(sub free) = 18.2%) for ail reflections without generated hydrogens. This refinement is proceeding. Comparisons of this 1.2 A microgravity structure to previous reports of the thaumatin structure at 1.75 A and to ground control crystals will be presented.
Document ID
20020024139
Acquisition Source
Marshall Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Kundrot, Craig E.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Barnes, Cindy L.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Snell, Eddie H.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Achari, Aniruddha
(NASA Marshall Space Flight Center Huntsville, AL United States)
Whitaker, Ann F.
Date Acquired
August 20, 2013
Publication Date
January 1, 2001
Subject Category
Solid-State Physics
Meeting Information
Meeting: American Crystallographic Association
Location: Los Angeles, CA
Country: United States
Start Date: July 21, 2001
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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