ABSTRACT
The study of the structure and function of biomolecules connects biology, biochemistry, chemistry, and physics. Biomolecules are truly complex; proteins have highly degenerate ground states. Proteins are the machines of life. They are constructed from twenty different building blocks, the amino acids. The final protein looks like a miniature crystal, consisting of the order of 1000 atoms and with linear dimensions of the order of a few nanometers. A closer look at the structure and function of a very important protein, hemoglobin, makes it clear, however, that motion is important. Hemoglobin transports oxygen and the dioxygen molecule is stored inside the hemoglobin during the ride from the lung to wherever O2 is used. In order to study the states and motions of a protein, we must look at a protein in action. The existence of substates leads to a separation of protein motions into two classes, equilibrium fluctuations and functionally important motions.
