The Role of Distortion in the Lysozyme-catalyzed Hydrolysis of Glucosides
Sykes, B.D. and David Dolphin
The chemical shift of the anomeric proton H1of the glucose ring and its apparent coupling constant to proton H2 can be obtained from the NMR spectrum of NAG-GLU-ΦpN02 . Upon the addition of lysozyme, the acetyl resonance shifts up field and broadens. The lifetimes for the exchange of the substrate between solution and the active site of lysozyme can be calculated from the linewidth of the acetyl resonance as a function of enzyme concentration. The calculated lifetimes satisfy the fast exchange conditions. Our results suggest that any change in the dihedral angle between H1 and H 2 of the glucose ring of the bound substrate is small; indicating that the glucose ring is not distorted when NAG-GLU-ΦN02 is bound to lysozyme. An alternative interpretation of these results is that only a small fraction of the bound substrate is distorted.