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

Abstract

Saturation of specific proton NMR signals from residues in the hydrophobic box region of [hen egg white] 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 were examined, and most were 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 known. A high correlation was observed between the observed nuclear Overhauser effects and interproton distances calculated from crystallographic 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 the nuclear Overhauser technique can be applied in a straightforward manner to obtain structural data in solution at the 1-.ANG. level.