Finding Water Molecules with Important Biological Activity

Published August 15, 2022

A schematic model for the hydrated phospholipid bilayer, which is a model of biological membranes.

A new ¹⁷O solid-state NMR technique, employed on the highest-field NMR spectrometer in the world (the 36 T Series Connected Hybrid), identifies water molecules in different layers of a model membrane for the first time.

What did scientists discover?

A new nuclear magnetic resonance (NMR) technique at 35.2T can identify ¹⁷O NMR signals of chemically and dynamically distinct water molecules. These signals are typically obscured by the large signals of bulk water.

Why is this important?

It is vital to understand the interactions of water molecules with proteins and membranes and their impact upon molecular structure and dynamics, as well as biological activity.

Water is ubiquitous and essential for the existence of all known life forms. Recently, it has been recognized that the mobility of water molecules in constrained biological systems is restricted and highly related to important biological functions. However, direct observation of these water molecules is challenging due to their extremely low populations compared to that of bulk water molecules. This new technique efficiently suppresses the large ¹⁷O NMR signals arising from bulk water molecules, thereby allowing for the detection of individual water molecules in a lipid bilayer environment, providing new opportunities to study biologically relevant water molecules in biological systems.

Who did the research?

Rongfu Zhang^1,2, Timothy A. Cross^1,2, Xinhua Peng³, Riqiang Fu¹

¹National MagLab; ²Florida State University; ³University of Science and Technology of China

Why did they need the MagLab?

High field magnets significantly improve both sensitivity and resolution of ¹⁷O NMR spectra of bound water molecules. The MagLab's 35.2T Series Connected Hybrid system, the highest-field NMR spectrometer in the world, is essential for this research.