Cross relaxation at the lysozyme–water interface: an NMR line-shape-relaxation correlation study

Abstract

In wet hen egg white lysozyme (HEWL), the molecular dynamics at the lysozyme–water interface was studied using a proton NMR line-shape-relaxation correlation approach that employed selective inversion of the proton magnetization. The intrinsic lysozyme proton spin-lattice relaxation rate, the intrinsic water proton spin-lattice relaxation rate, and the lysozyme proton – water proton cross-relaxation rate were determined. The lysozyme proton – water proton intermolecular interaction couples these protons and contributes to spin-lattice relaxation as well. The results suggest that a minimum of three different correlation times are needed to characterize the water molecule dynamics in wet HEWL.

Macromolecule and water magnetization exchange modeling in articular cartilage

“…4). The observation of such a negative reconstructed FID, with associated T 1 shorter than the minimum T 1 found in the T 1 HH results (Table 2), provided strong evidence for magnetization exchange between a solid‐like and a liquid‐like spin reservoir (16, 25). In our cartilage samples exchange was detected between the S and L2 spin reservoirs which proceeded at a relativity high rate.…”

Water molecule dynamics in hydrated lysozyme. A deuteron magnetic resonance study

“…8 for k with the parameters found for the anisotropic motion model (legend to Fig. 2) and the above 01 and r, we calculate k = 44 s-' at 40 MHz and 293 K. In a two-dimensional NMR time evolution study of proton magnetization in wet HEWL at the same frequency and temperature, a value for k = (98 ± 16) s-1 was deduced (22). Although the two values of k differ by a factor of -2, the results are nevertheless encouraging.…”

“…However, it must be kept in mind that such predicted rates are to be compared with the intrinsic water proton rates Rlwi and R2wi rather than the observed relaxation rates. In a recent study of cross-relaxation effects in wet HEWL at 40 MHz (22), it was shown that at room temperature the water-HEWL cross-relaxation rate had a value of -100 s'-i. This is approximately one-sixth of the observed proton rate R2W but >10 times as large as the observed rate R,W (8).…”

Proton and Deuteron Relaxation Study of Molecular Dynamics in Lysozyme Solutions

“…Unfortunately, the observed water proton rates cannot be used directly to deduce dynamical information about the water molecules in protein solutions with absolute confidence due to possible contributions from water proton -protein proton intermolecular coupling that may produce spin-lattice relaxation and/or magnetization exchange effects [40][41][42]. In addition, exchange of labile protein hydrogens may play an important role [29].…”