Why Water is Essential to Life as We Know It

Scientists are getting closer to directly observing how and why water is essential to life as we know it.

A study in this week’s Proceedings of the National Academy of Sciences provides the strongest evidence yet that proteins – the large and complex molecules that fold into particular shapes to enable biological reactions – can’t fold themselves.

Rather, the work of folding is done by much smaller water molecules, which surround proteins and push and pull at them to make them fold a certain way in fractions of a second, like scores of tiny origami artists folding a giant sheet of paper at blazingly fast speeds.

Dongping Zhong, leader of the research group at The Ohio State University that made the discovery. It is a major step forward in the understanding of water-protein interactions and it answers a question that’s been dogging research into protein dynamics for decades.

The key to getting a good view of the interaction was to precisely locate optical probes on the protein surface, he said. The researchers inserted molecules of the amino acid tryptophan into the protein as a probe, and measured how water moved around it.

Co-authors on the study were Yangzhong Qin, a postdoctoral researcher, and Lijuan Wang, lab manager. The work was funded by the National Institutes of Health, and computing time was provided by OSC.