Brazzein is a remarkable protein, first isolated from a West African berry, that, without any carbohydrate, is 17,000 times sweeter (on a per-molecule) basis than sucrose. Our goal is to use this protein to learn more about the human sweet taste receptor.
Color code: red, enhanced sweetness; light blue, moderately decreased
sweetness; dark blue, strongly decreased sweetness; dark gray,
sweetness equivalent to wild-type; light gray, residues not yet mutated
(Assadi-Porter et al., 2000).
The central theme of our research is the application of nuclear
magnetic resonance (NMR) spectroscopy to the solution of biochemical
problems. The unique power of NMR lies in its ability to provide
detailed chemical and structural information at an atomic level about
molecules in solution--even when they are present in living cells or
organisms. The general strategy is to use multidimensional (2D, 3D, and
4D), multinuclear magnetic resonance techniques to detect and assign
resonances from atoms of biological interest (e.g., 1H, 13C, 15N, and 31P).
With these assignments in hand, we can then interpret the wealth of
spectral information present in coupling constants, relaxation rates,
cross-relaxation rates, and chemical shifts. Proton-proton
cross-relaxation rates and a variety of measured coupling constants are
used to derive three-dimensional structures of these macromolecules.
Relaxation rates, line-shapes, and nuclear Overhauser effect
measurements provide information about molecular motions and