An understanding of the crystal structure of serum albumin is critical in the development of new human pharmaceuticals. A detailed knowledge of the three-dimensional structure of serum albumin, especially the human form, is imperative in order to fully understand the binding nodes and physical properties of this multifaceted protein. Difficulties in crystal size, quality and reproducibility have resulted in the three-dimensional structure of serum albumin being relatively unknown. This invention results in large, high-quality crystals suitable for x-ray structure determination.

Potential Commercial Uses

Human serum albumin (HSA) contributes to many transport and regulatory processes in the body. It has multifunctional binding properties which range from various metals, calcium and copper, to fatty acids, hormones and therapeutic drugs. Distribution, free concentration, and metabolism of various pharmaceuticals can be significantly altered as a function of the magnitude of binding with HSA.

Benefits

The benefits of this process will allow for better growth of HSA crystals, which will be larger, more uniform, and reproducible. The relatively high quality crystals are suitable for x-ray structure determination. Crystalline arrays containing the serum albumin protein and drug molecules can be produced. Details of the molecular interaction between a variety of pharmaceutical drugs and the protein can be determined.

The Technology

Crystal growth may be readily carried out by a "hanging drop" method using a polyethylene glycol (PEG) solution and a monobasic potassium phosphate buffering agent, with solution pH being adjusted prior to initiation of crystal growth. While hanging drop is the technique used, crystal growth can also be achieved by vapor diffusion, dialysis, or batch methods. In the hanging drop method, the solution should contain PEG at a molecular weight of 180Ð800, a concentration of 35Ð45 volume percent, and a monobasic potassium phosphate concentration of 0. 05 to 0.1M to provide the required pH of 4.6Ð7.2. In a preferred solution, the precipitant solution pH is adjusted after mixing to compensate for variations in pH which arise from variation in molecular weight and residue content of PEG. In carrying out the hanging drop method, a droplet of this solution, approximately 10 microliters and an equal droplet of precipitant solution, would be placed on a coverslip and allowed to mix. A larger amount, about 1microliter of precipitant solution, without HSA, would be disposed in the well of the apparatus. Crystals grow from these periods in 3Ð10 days to dimensions of 0.05 ´ 0.5 ´ 0.5 mm to 2.0 ´ 2.0 ´ 0.3 mm. The variations in the times for crystal growth are a function of protein concentration and pH. For x-ray diffraction experiments, the crystals are transferred from the hanging drop to a 10 to 20 microliter droplet of the corresponding reservoir solution. The crystals are stable in these solutions.

Options for Commercialization

The human serum albumin crystal growth process is part of NASA's Technology Transfer Program and is available for licensing. A patent for this process has been issued to NASA and is one of several available through MSFC.

Patent Number

4,833,233

Contact for Licensing Information

Technology Transfer Office
Patent Licensing Information
Mail Code CD30
Marshall Space Flight Center, AL 35812

Key Words

Serum Albumin
Crystals
Human
Hanging Drop
X-Ray Diffraction
Polyethylene Glycol
Protein
Pharmaceuticals

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