Freeze-fracture electron microscopic analysis of solutions of biological molecules

Freeze-fracture electron microscopy was used to study the morphology of proteins in solution. The size of the particles appearing on the fractured surface, replicated with tungstentantalum, were measured in a direction perpendicular to the shadowing angle. The distributions of the measured particle sizes could be correlated with the known shape and dimensions for each protein. It is concluded that freeze-fracture electron microscopy is a useful technique to study the morphology of biological molecules in solution, particularly hydrophobic proteins which may be difficult to study by other microscopic techniques.