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Space Station Internal Payloads
Commercial Protein Crystal Growth-High Density (CPCG-H)
Missions: Expedition Two, ISS Mission 6A, STS-100 Space Shuttle Flight, return flight 7A.1, STS-105
Experiment Location on ISS: U.S. Lab EXPRESS Rack 1
Principal Investigator: Dr. Larry DeLucas, Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham
Project Manager: John West, NASA's Marshall Space Flight Center, Huntsville, Ala.
Proteins are the building blocks of our bodies, and the living world around us. Within our bodies, some proteins make it possible for red blood cells to carry oxygen, while others help transmit nerve impulses that allow us to see, hear, smell, and touch. Other proteins play crucial roles in causing diseases. Pharmaceutical companies may be able to develop new or improved drugs to fight those diseases once the exact structure of the proteins are known.
The goal of the Commercial Protein Crystal Growth payload is to grow high-quality crystals of selected proteins so that their molecular structures can be studied. On Earth, gravity often has a negative impact on growing protein crystals. In microgravity - the near weightlessness of space - gravity's disturbances are removed, allowing crystals to grow in a more regular and perfect form.
When the microscopic crystals are returned to Earth from the International Space Station, scientists will use X-rays to help analyze the crystals and to map the locations of a protein's atoms. This information allows them to make computer models depicting the biological molecules and to determine how the biological substances function. Knowing the atomic structure may help pharmaceutical companies develop medicines that fit into a protein's structure - much like a key in lock. This research may lead to more effective medicines with fewer side effects.
The Center for Biophysical Sciences and Engineering, formerly the Center for Macromolecular Crystallography, at the University of Alabama at Birmingham (UAB) is one of NASA's Commercial Space Centers (CSCs). These centers partner with industry to perform commercially driven research on Earth and in space.
Grow large, well-ordered protein crystals in microgravity.
Sample trays(HDPCG) are mounted in a C-RIM, able to conduct 1008 individual experiments.
Flight Operations Summary
This payload is continuously powered and utilizes the CRIM. The crew is involved in activation, deactivation, transfer, periodic filter cleaning and temperature monitoring. The crew will also be able to work a few malfunction procedures.
The Commercial Protein Crystal Growth payload consists of 1,008 individual experiments in the High Density Protein Crystal Growth Assembly. This assembly will be stored in a Commercial Refrigerator Incubator Module for temperature control. The payload will be transferred to the International Space Station and the experiments will be activated. The crystal growth experiments, which require minimal crew interaction, will continue through the duration of the mission. The High Density Protein Crystal Growth System represents a major increase in capacity over the Center's previous crystal growth hardware, which contained 128 individual experiments.
The experiment is scheduled for launch onboard the Space Shuttle mission STS-100, part of ISS mission 6A in April 2001. The Commercial Protein Crystal Growth payload will occupy one locker in EXPRESS Rack 1 in the U.S. Lab on the Space Station. The CPCG-H payload is scheduled to return to Earth onboard the Shuttle STS-105 mission in July 2001.
Crew involvement during this time will be to transfer the incubator module from the Shuttle to the Space Station - scheduled for no later than Flight Day 7 -- activate the experiments, and conduct daily status checks. These daily checks consist of checking temperature readings and cleaning the air filter. When the payload is scheduled to return to Earth, the crew will deactivate the experiments and return the module from space.
On board the Space Station, protein crystals will be grown inside the High-Density Protein Crystal Growth Assembly using the vapor diffusion process.
Each experiment chamber in the CPCG-H consists of a small chamber to hold the protein crystal solution and reservoir chamber to hold the precipitating agent solution. A small droplet of protein solution is mixed with a small amount of precipitating agent solution and placed in the protein chamber. The larger chamber is filled with more concentrated precipitating agent solution, which is captured in a polymer wicking material to keep the solution from moving around the chamber. During activation, the protein chamber is rotated so that it is in vapor contact with the reservoir. Water molecules migrate from the protein droplet through the vapor space into the more concentrated reservoir. As the volume of the protein droplet decreases, the concentration of protein increases and protein crystals form. As the experiment proceeds, the crystals become larger.
These protein crystals will be returned to Earth and studied using a process called X-ray diffraction. Scientists send a beam of X-rays through the crystal and measure how the atoms in the crystal bend the X-rays. By studying the pattern made by the X-rays, scientists can map the locations of the different atoms, allowing them to create a 3-dimensional model of the protein. With this structural information, researchers can then determine how the protein functions and design drugs to mediate the function of the protein. This process, known as structure-based drug design, may lead to more effective drugs that target specific proteins.
Protein crystal growth experiments have been conducted by the Center for Biophysical Sciences and Engineering on 38 previous Space Shuttle missions, beginning in 1985.
Structural studies using microgravity-grown protein crystals may provide information that can be used in the development of new drugs. With the advent of genomic information from humans and many other species, the roles proteins play in diseases and degenerative conditions is becoming more clear and the need for information about the structure of these proteins more critical.
Further biological structure growth experiments will be part of the ongoing research conducted aboard the International Space Station. The Space Station provides a platform for growing some crystals that require longer periods of microgravity than has been available on short duration Space Shuttle flights.
Benefits from microgravity protein growth experiments have already been seen. Many of the crystallization experiments conducted on the Space Shuttle have yielded crystals that furthered structural biology projects. For example, microgravity crystallization experiments have been conducted with recombinant human insulin. These studies have yielded X-ray diffraction data that helped scientists to determine higher-resolution structures of insulin formations. This structural information is valuable for ongoing research toward more effective treatment of diabetes. Other very successful microgravity crystallization experiments have provided enhanced X-ray diffraction data on a protein involved in the human immune system. These studies have contributed to the search for drugs to decrease inflammation problems associated with open-heart surgery.
The crystallization of proteins in the microgravity environment has developed into a valuable and necessary tool for the science of macromolecular crystallography. Crystallization experiments conducted on the International Space Station, involving not only human but also animal and plant proteins, promise to help answer key questions about the world around us.
Additional information and photos on this Expedition Two experiment is available at: