A structural study of the hydrophobic box region of lysozyme in solution using nuclear Overhauser effects

Saturation of specific proton nuclear magnetic resonance (NMR) signals from residues in the hydrophobic box region of lysozyme (EC 3.2.1.17) has enabled negative nuclear Overhauser effects to be measured on the resonances of nearby protons. The assignments of resonances reported previously have been examined, and most have been confirmed. In conjunction with spin-decoupling methods, new assignments could be made so that assignments for some 70 resonances of 25 residues in lysozyme are now known. A high correlation was observed between the observed nuclear Overhauser effects and interproton distances calculated from cyrystallographic data. This indicates that the average structure of this region of lysozyme in the crystalline state is maintained in solution, that substantial populations of structures very different from this do not exist, and that the nuclear Overhauser technique can be applied in a straightforward manner to obtain structural data in solution at the 1-A level.