Nuclear magnetic resonance and isotope-exchange techniques were used to stu
dy unfolding of lysozyme adsorbed to reversed-phase liquid chromatography s
urfaces. All surfaces resulted in significant amide exchange, indicating so
lvent exposure and some loss of native structure. However, none of the surf
aces resulted in complete exchange. The greatest amount of structure was pr
eserved on the C-4 silica, with the most protection in the alpha-helix doma
in. C-18 silica and Source RPLC resulted in much greater solvent exposure.
No simple correlation was found between chromatographic retention and degre
e of surface unfolding. Variations in residual conformation may explain the
complex retention behavior of proteins vs. small molecules. (C) 1999 Elsev
ier Science B.V. All rights reserved.