diffraction resolution and quality of data for the crystals produced in microgravity were
increased when compared to the diffraction resolution of the crystals grown on Earth (Vahedi-
Faridi 2003).
High-resolution structural data were also obtained from human albumin and human
antithrombin III crystals.
PCG-STES-VEKS
The PCG-STES-VEKS operated on the ISS during Expeditions 2, 4, 5.
The experiment used precipitants of ammonium sulfate, sodium
chloride, 2-methyl-2,4-pentanediol, and polyethylene glycol. The
samples that used ammonium sulfate and sodium chloride
showed that activation of 4 days provides equilibrium, while
activation for 2 days provides 90% equilibrium. This indicates that
shuttle missions of 10 days are long enough to allow salt
samples to reach equilibrium. For the remaining samples, time
to equilibrium is dependent on the drop volume; at the highest
volume, it takes approximately 10 days to reach equilibrium.
(Achari, Increments 2 and 4 One Year Postflight Reports).
Expedition 5 used 9 trays in PCAM 6 on flight STS-111/UF2. The sample in 7 of the 9 trays lost
volume during the experiment. The space shuttle mission was unexpectedly extended, which
might explain the loss of volume in the trays. Due to the loss of volume, the kinetics data was
not obtained (Achari, Increment 5 One Year Postflight Report).
PUBLICATION(S)
Vahedi-Faridi A, Porta J, Borgstahl GEO. Improved three-dimensional growth of manganese
superoxide dismutase crystals on the International Space Station. Acta Crystallographica
Section D: Biological Crystallography. 2003;59(Pt 2):385-388. doi:
10.1107/S0907444902020310.
This investigation is complete and all results are published.
Protein Crystallization Apparatus
for Microgravity (PCAM). NASA’s
Marshall Flight Space Center
image.