Portland State University. Department of Physics
Date of Award
Master of Science (M.S.) in Physics
1 online resource (vii, 41 leaves, ill. 28 cm.)
Lactoglobulin, Electron microscopes
Often electron micrographs exhibit a repeating structure. Sometimes this repeating structure satisfies the definition of a crystal in that it has a three dimensional repeating structure. If the unit cell structure of this repeating structure can be determined it can be used to help categorize different sections of a particular sample. In some cases, the use of optical diffraction analysis of electron micrographs with repeating structure is a method of determining the unit cell structure.
Samples of β-Lactoglobulin were prepared for viewing in the electron microscope using both the crystalline material and carbon replicas of the crystal surface. Because the crystalline material was very unstable in the electron beam, images adequate for use as diffraction gratings could not be obtained. Electron images from the replicas were used to generate the optical diffraction patterns in this paper.
The structure of β-Lactoglobulin has been determined previously by X-ray diffraction analysis. This information was used to assist in the interpretation of the optical diffraction patterns.
Electron micrographs and optical diffraction patterns were recorded which were found to be consistent with the structure of β-Lactoglobulin which were found to be consistent with the structure of β-Lactoglobulin as determined by X-ray diffraction analysis. The unit cell dimensions were determined to be a = 58±4Å, b = 59±3Å and c = 102±12Å.
Roeter, Richard, "Crystal structure determination of β-lactoglobulin from electron micrographs" (1971). Dissertations and Theses. Paper 1479.