cellular processes as well as of protein and nucleic acid leading to custom enzymes, ribozymes,
or inhibitors to treat diseases.
APCF-CAMELIDS (WYNS)
Four of the 6 reactors used for APCF-Camelids produced crystals. Optical analysis and
interferometry were used to determine the crystals’ properties that included a maximum
resolution of 1.2A. This was much better than crystals grown under similar conditions on Earth
and comparable to the best resolution ever achieved for crystals grown in hanging-drop
experiments aboard the shuttle.
APCF-CRYSTAL GROWTH (WEINKAUF)
After their return to Earth, the ferritin crystals were found to have better diffraction than Earth-
grown crystals but the data collection was incomplete. The lumazin synthase crystals had
diffraction properties equal to those grown on Earth.
APCF-CRYSTAL QUALITY (GIEGE)
Crystallographic analysis indicates that the space-grown crystals
are superior to the control-group crystals grown on Earth. Crystals
grown in microgravity generally have improved morphology,
larger volume, better optical properties, higher diffraction limit,
and lower mosaicity when compared to Earth-grown crystals.
Several space-grown crystals including Aspartyl-tRNA Synthetase
and thaumatin have a common feature; an increased number of
ordered hydrogen-bound water molecules in the hydration layer
of the protein. This may be responsible for the enhanced stability
of the protein crystals (Vergara 2005).
Well-diffracting crystals prepared in space have 2 purposes:
understanding the gravity-dependent phenomena (such as
nucleation and growth mechanisms) and structural determination. Each new high-resolution
structure may become the start of a cascade of investigations to unravel the complexity of the
cellular events like growth, division, differentiation, communication, motility, death, and their
role in the development of multicellular organisms. This may
accelerate the structure-based design and redesign of drugs
targeting pathogens, diseases and degenerative cellular
processes as well as of protein and nucleic acid leading to
custom enzymes, ribozymes, or inhibitors to treat diseases.
APCF-LIPOPROTEIN (BAUMSTARK)
Although APCF-Lipoprotein successfully produced crystals,
the main objective of achieving a significant improvement in
resolution (compared to Earth-grown crystals) was not
accomplished. However, there was some indication that
parameters like mosaicity and the signal/noise ratio were in fact improved.
Computer generated image of
a ferritin molecule. NASA
image.Computer generated image of
a lysozyme molecule. NASA
image.