Hydration Structure Changes of Proteins at Work

Abstract

As described in Chaps. 4, 7 and 8, the shell of hydration water molecules wraps protein surfaces and is pinned to polar protein atoms at several places. When the hydration shell retains persistently, water molecules residing on the surface concaves hinder large-scale conformational changes of proteins necessary for their functions. Therefore, hydration structures must reorganize flexibly and dynamically in concert with the conformational changes of proteins. In this chapter, we focus on hydration structure changes in large-scale domain motion of glutamate dehydrogenase. Hydration structure changes in the active-site cleft of the enzyme were visualized by X-ray crystallography and molecular dynamics simulation. We found that hydration structures have a remarkable influence on global conformational changes of proteins. In addition, we introduce an experimental approach to regulate the conformation and hydration of proteins by controlling relative humidity around protein crystals.