Europe’s Advanced Protein Crystallisation Facility (APCF), launched with
Shuttle mission STS-105 on 10 August, was transferred on Tuesday 14 August
from its transport position in the Shuttle’s mid-deck to its on-orbit
accommodation in Express Rack 1 in the US laboratory Destiny.
The transfer had to be carried out relatively quickly because the temperature
of the incubator in the APCF needs to be permanently maintained at the correct
level, so it can only remain without power for a limited period of time. Two
hours after the transfer, at 16:02 GMT, the facility was switched on by the
astronauts and the pre-programmed sequence of activating different reactors,
in which protein crystals will grow, was started.
With the activation of the APCF, the European utilisation of the International
Space Station has formally started.
The APCF, Europe’s first experiment facility to arrive at the ISS, will
perform a series of automated experiments that could be a step towards a
better understanding of protein crystallisation. ESA’s prime contractor for
the APCF is Astrium.
Protein molecules are quite literally the substance of life. These vast
arrays of atoms perform just about every important biochemical function
inside living cells. They store and carry biological information; they act
as catalysts in the hugely complex chemistry of life; and they provide
membranes and cell walls.
Proteins are principally composed of amino acids, themselves made up of
mainly carbon, hydrogen, oxygen and nitrogen. There are relatively few
possible amino acids, but they can arrange themselves in an almost infinite
number of ways, creating huge molecules that loop and fold into shapes of
awesome complexity. The shape and structure of each protein is what gives
it its special abilities.
If scientists can map that structure, they can learn more about the intimate
workings of life. They will then be able to use their knowledge to synthesise
proteins in the laboratory, which can lead to dramatically effective drugs.
This is no easy task.
To analyse protein structure, scientists use a technique called X-ray
crystallography — and for that technique to deliver the data they are after,
they need to have structurally well-ordered crystals. But proteins do not
crystallise easily and it is the perfect crystals that X-ray studies require
that are especially hard to make. Without the interfering tug of the Earth’s
gravity, the quality of the crystals may be improved, which is why the APCF
will be heading for the International Space Station.
Nevertheless, even in the station’s microgravity environment, to grow protein
crystals can be difficult. Previous experiments — performed both by ESA
and NASA have not always provided satisfactory explanations of the results
obtained. A thorough analysis of the crystal growth process itself has
enabled leading European scientists to design a new ‘reactor’ for crystal
formation which proved very efficient on previous flights. As well, a method
for three-dimensional imaging utilising the APCF optical diagnostics
capabilities was conceived, that will allow scientists to make very precise
observations of every stage of the process.
This new APCF experiment will run for more than three months, longer than
most previous attempts. When the crystal samples return to Earth in December
with utilisation flight UF-1, researchers will be hoping for an early
Christmas present.
Related Links
* STS-105 mission updates
http://spaceflight.nasa.gov/shuttle/
* ISS assembly flight 7a.1
http://spaceflight.nasa.gov/station/assembly/flights/2001/7a1.html
* Astrium Space
IMAGE CAPTIONS:
[Image 1:
http://www.esa.int/export/esaCP/ESA43I1VMOC_index_1.html]
APCF for Destiny — the facility has been modified for the International Space
Station.
[Image 2:
http://www.esa.int/export/esaCP/ESA43I1VMOC_index_1.html#subhead1]
APCF Experiment Reactors – Vapour Diffusion, Free Interface Diffusion, Dialysis.
