A new study has explained that why water is considered as the basic unit of life and why life is not possible without it.
The Ohio State University lead researcher Dongping Zhong called the study a 'major step forward' in the understanding of water-protein interactions and said it answers a question that's been dogging research into protein dynamics for decades.
Zhong, who is also a professor of chemistry and biochemistry and his team used ultra-fast laser pulses to take snapshots of water molecules moving around a DNA polymerase, the kind of protein that helps DNA reproduce.
The researchers inserted molecules of the amino acid tryptophan into the protein as a probe and measured how water moved around it.
The research showed water molecules typically flow around each other at picosecond speeds, while proteins fold at nanosecond speeds, 1,000 times slower. Previously, Zhong's group demonstrated that the water molecules slow down when they encounter a protein. Water molecules are still moving 100 times faster than a protein when they connect with it.
In the new study, the researchers were able to determine that the water molecules directly touched the protein's 'side chains,' the portions of the protein molecule that bind and unbind with each other to enable folding and function. The researchers were also able to note the timing of movement in the molecules.
Water can't arbitrarily shape a protein, Zhong explained. Proteins can only fold and unfold in a few different ways depending on the amino acids they're made of.
The study is published in the Proceedings of the National Academy of Sciences journal.
