Hydration Studies

Summary

In the context of structural studies with biological macromolecules, in particular proteins and DNA, the special character of interior and surface-bound water molecules is of interest. These "hydration water molecules" can interact in many different ways with macromolecules, and some are considered to form an integral part of protein or DNA three-dimensional structures. Examples of tightly bound water molecules are the "spine of hydration" in the minor groove of B-DNA, or the four interior water molecules in the trypsin inhibitor BPTI; for both systems these water molecules have been observed by both x-ray crystallography and by NMR. A special role adopted by hydration water molecules is the bridging between two macromolecules, e.g., between the specific complexes formed by DNA-binding proteins and their target DNA, which appear in many instances to be essential for the specific DNA-recognition by the protein. Complementary information about hydration water molecules results from single crystal x-ray diffraction, and from NMR measurements in solution. Often signals from amino acid side chain hydroxyl groups interfere with hydration water measurements. For this reason we prepared a small protein devoid of all serine and threonine residues. With the use of this newly designed protein we investigated the feasibility of identifying the complete layer of hydration waters on the surface of globular proteins.

Index Terms

Hydration Water, Protein Hydration, Protein-DNA Complexes

Supported By

Schweizerischer Nationalfonds

In Collaboration With

Dr. H. Iwai, Dr. A. Sobol, Prof. K. Wüthrich