Analytical ultracentrifugation

Analytical_ultracentrifugation

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  Analytical ultracentrifugation
• Rotors for Analytical Ultracentrifuge
  Rotors for Analytical Ultracentrifuge

Analytical Ultracentrifugation

Analytical ultracentrifugation (AUC) is a powerful technique used in the field of biochemistry and molecular biology to study the properties of macromolecules in solution. It allows researchers to determine the molecular weight, shape, and interactions of proteins, nucleic acids, and other macromolecules.

Principles

Analytical ultracentrifugation involves the use of a high-speed centrifuge to apply a strong centrifugal force to a solution containing the macromolecules of interest. This force causes the molecules to sediment at different rates depending on their size, shape, and density. By analyzing the sedimentation behavior, researchers can gain insights into the physical properties of the molecules.

There are two main types of analytical ultracentrifugation experiments: sedimentation velocity and sedimentation equilibrium.

Sedimentation Velocity

In a sedimentation velocity experiment, the rate at which molecules move through the solution under the influence of the centrifugal force is measured. This provides information about the size and shape of the molecules. The data obtained can be used to calculate the sedimentation coefficient, which is a measure of how fast a particle sediments in a centrifugal field.

Sedimentation Equilibrium

Sedimentation equilibrium experiments are used to determine the molecular weight of macromolecules. In this type of experiment, the centrifugal force is applied until the system reaches equilibrium, where the sedimentation of the molecules is balanced by diffusion. The distribution of molecules at equilibrium can be analyzed to determine their molecular weight and interactions.

Applications

Analytical ultracentrifugation is widely used in the study of protein-protein interactions, protein-DNA interactions, and the characterization of complexes such as virus particles and lipoproteins. It is also used to study the oligomeric state of proteins and to analyze conformational changes in macromolecules.

Advantages

One of the main advantages of analytical ultracentrifugation is that it does not require the macromolecules to be labeled or modified, allowing for the study of molecules in their native state. It is also a versatile technique that can be applied to a wide range of molecular sizes and types.

Related Pages

• Centrifugation
• Molecular weight determination
• Protein structure
• Biophysical techniques