  Water is essential for the activity of proteins. However, the effect of the
properties of water on the behavior of proteins is only partially understood.
Recently, several experiments have investigated the relation between the
dynamics of the hydration water and the dynamics of protein. These works have
generated a large amount of data whose interpretation is debated. New
experiments measure the dynamics of water at low temperature on the surface of
proteins, finding a qualitative change (crossover) that might be related to the
slowing down and stop of the protein's activity (protein glass transition),
possibly relevant for the safe preservation of organic material at low
temperature. To better understand the experimental data several scenarios have
been discussed. Here, we review these experiments and discuss their
interpretations in relation with the anomalous properties of water. We
summarize the results for the thermodynamics and dynamics of supercooled water
at an interface. We consider also the effect of water on protein stability,
making a step in the direction of understanding, by means of Monte Carlo
simulations and theoretical calculations, how the interplay of water
cooperativity and hydrogen bonds interfacial strengthening affects the protein
cold denaturation.
