New Capacity for Membrane Protein Structural Characterization by NMR Spectroscopy Discovered at the NHMFL

May 17, 2000

Contact:
Janet Patten, (850) 644-9651

TALLAHASSEE, Fla. – Biophysicists at the National High Magnetic Field Laboratory (NHMFL) have discovered a new approach for characterizing the three dimensional structures of membrane proteins. The approach is based on the unique pattern of signals displayed in nuclear magnetic resonance (NMR) spectra.

Membrane proteins represent one of the great frontiers of structural biology today. These proteins are responsible for communication between the outside world and the chemical and biological factories that are housed inside the cell membranes. Ninety percent of today's neuroscience drug targets are membrane proteins. These proteins are responsible for transmitting hormonal signals into the cell and for transporting nutrients into the cell and products out of the cell. Modulating the efficiency of these proteins can be critical for the control of cell and tissue performance and for the control of disease states.

As important as these proteins are to cellular processes, they have been extraordinarily difficult to characterize by standard technologies and techniques. Consequently, only about 20 membrane proteins are understood today.

Researchers Tim Cross, Riqiang Fu, and Jack Quine and their coworkers at the NHMFL discovered that the signal patterns observed in two dimensional spectra directly reflect the distribution of amino acids around a helical axis, known as a helical wheel. Now, through standard methods of isotopic labeling using bacterial cultures, it is possible to assign these signals to specific atomic sites in the membrane protein helices. Traditionally, without knowing where in the molecule each signal comes from, it has been difficult to make any progress with structural characterization of membrane proteins. This important research is supported by the National Science Foundation's Molecular Biophysics Program and has just been published as the cover story in the May issue of the Journal of Magnetic Resonance.

The NHMFL is funded by the National Science Foundation and the State of Florida. It is operated by a consortium comprising of Florida State University, the University of Florida, and Los Alamos National Laboratory. The NHMFL is a dedicated national user facility providing state-of-the-art magnets for research in all areas of science, including biology, bio-medicine, chemistry, geology, engineering, materials science, and physics. The NHMFL is the largest and highest-powered laboratory of its type in the world and the only one in the Western Hemisphere.