PRESSURE-INDUCED CHANGES IN THE FOLDED STRUCTURE OF LYSOZYME

We demonstrate, for the first time in solution, that pressure induces changes in the overall folded structure of a protein (lysozyme). This was made possible by using a home-developed, on-line continuously vari able pressure cell on a high resolution NMR spectrometer operating at 750 MHz. We could follow pressure-induced diamagnetic chemical shifts of more than 26 protons of lysozyme at variable pressure in the range of 1 to 2000 bar. The results indicate that the main effect of the pre ssure is a compaction of the hydrophobic core part of the protein cons isting of bulky side-chains. The technique introduced here provides a general method with which one can probe microscopic internal flexibili ty of a protein in solution. (C) 1997 Academic Press Limited.