Fig 1.

(Upper) X-ray crystal structure of the protein Monellin. The structure was downloaded from the PDB (ID code ) and processed with the program WEBLAB-VIEWERLITE to show only one of the monomers. In solution, Monellin exists as a monomer (9, 14). (Lower) Steady-state fluorescence spectra of 100 μM Monellin in a 0.1 M phosphate buffer (native state) and in a 6 M Gdn⋅HCl solution (denatured state). Also, we include fluorescence spectra of Trp in solution of the same concentration. The excitation wavelength was 295 nm.