Protein-water interactions, lysozyme

Protein—Water Interactions in Human and Tortoise Lysozymes ... 

Carerl, G.C. Gratton, E. Yang, P.-H. Rupley, J.A. "Protein-Water Interactions. Correlation of Infrared Spectroscopic, Heat Capacity, Diamagnetic Susceptibility and Enzymatic Measurements on Lysozyme Powders," submitted for publication, 1979. 

Yang P-H, Rupley JA. 1979. Protein-water interactions. Heat capacity of the lysozyme-... 

Figure 11.6 shows the FST-based analysis of GuHCl-denaturation of lysozyme. At lower GuHCl concentration, the denaturant-induced equilibrium shift -3A,GV3p3 is determined predominantly by AA23. As the concentration increases, the contribution from the protein-water interaction becomes more important. Combining this with Equation 11.2 and Equation 11.9, one can show that AA 2i must have the opposite sign... 

Separations in hydrophobic interaction chromatography have been modeled as a function of the ionic strength of the buffer and of the hydrophobicity of the column, and tested using the elution of lysozyme and ovalbumin from octyl-, butyl- and phenyl-Sepharose phases.2 The theoretical framework used preferential interaction analysis, a theory competitive to solvophobic theory. Solvophobic theory views protein-surface interaction as a two-step process. In this model, the protein appears in a cavity in the water formed above the adsorption site and then adsorbs to the phase, with the free energy change... 

Figure 3. Dependence of the second virial coefficient on the concentration of cosolvent in the water (1)—lysozyme (2)—arginine (3) mixture. , experimental data solid line, values predicted using eq 10 with722 (see Table 2) as an adjustable parameter , protein—solvent interaction contribution B " calculated using eq IIB O, ideal mixture contribution B (eq 11 A) A, protein—protein interaction contribution B " P predicted by eq 11C with 722 as an adjustable parameter from Table 2. See details in Figure 1.

Figure 4. Dependence of the second virial coefficient on the concentration of NaCl in a water (1)—lysozyme (2)—NaCl (3) mixture. B22 (broken line) was calculated using eq 10 with bothyri andyri used as adjustable parameters found by fitting the experimental data ( , ref 48 O, ref 19 and , ref 28). ideal mixture contribution predicted using eq 11 A protein—solvent interaction contribution calculated...

The interaction of /3-casein molecules with lecithin monolayers is governed by the surface activity (hydrophobicity) of the macromolecule. Hydrophobicity does not guarantee interaction of a protein with lecithin in dispersion (22), but it favors penetration of proteins into monolayers at the air-water interface. The whole molecule seems to penetrate in the case of /3-casein (Figure 7) this leads to the compression of the lipid molecules and perhaps the formation of a layer of relatively restricted lecithin molecules around the periphery of the protein molecules. The situation is quite different for a very polar protein such as lysozyme where... 

Relaxation Measurements. NMR measurements have been used to examine water-protein interactions in solution and in hydrated powders (2). Hilton et al (24) have shown that the motional properties of water in partially hydrated powders of lysozyme are best characterized as those of a viscous liquid. Dielectric relaxation spectra of water in lysozyme powders (28) distinguish... 

Other studies included the investigation of the stabilizing effect of sorbitol on hen egg white lysozyme and the use of the self-diffusion coefficient, D, to follow the solution and aggregative properties of lysozyme at different pH, temperature, and protein and salt concentrations. The properties of frozen ovalbumin solutions were studied by NMR relaxation spectroscopy. It is known that the functional properties of muscle proteins are affected by protein interactions with ions, and NMR was used to assess protein/water, protein/salt, and protein/protein interactions in myofibrillar protein solutions. Previous X-ray and NMR studies on collagen and peptides were reviewed by Mayo and, more recently, such types of system were characterized by high-resolution H and C NMR. °0 The structure, hydration state, and nature of the interactions between water and gelatin were determined by time domain NMR. ... 

Abstract The self-diffusion coefficients of water and lysozyme in aqueous solution have been measured over a wide range of the protein concentration and over a wide range of temperature by means of the pulsed-high-field-gradient spin-echo H NMR method, and also the 0 NMR spectra of water in the protein solutions have been measured by means of a solution 0 NMR method, in order to elucidate the structure and dynamics of water and the protein, and intermo-lecular interactions between water and the protein. From these experimental results, it is found that there exist two types of water molecules with different diffusion components... 

From such a background, we aimed to measure selfdiffusion coefficients, D, of water and lysozyme in aqueous lysozyme concentrated solution at high concentration and also over a wide range of protein concentrations as a function of temperature by the PHFGSE H NMR method and to measure 0 NMR spectra of aqueous lysozyme concentrated solution, and to elucidate intermolecular interactions between the protein and water through the diffusion coefficient determined and the NMR spectra, in addition to... 

Following the original work by Kauzmann on hydrophobic interactions and the determinations of the structures of myoglobin and hemoglobin, it was stated, and is still stated frequently (despite evidence to the contrary), that hydrophobic residues are buried in the interior of proteins and hydrophilic residues are exposed to solvent water. It was first shown by Klotz (1970 see also Lee and Richards, 1971) that a substantial proportion of the exposed solvent-accessible surface area of proteins is composed of nonpolar groups. This matter has been stressed in lectures for many years by one of the authors (H. McK.) (for a discussion of various approaches to this problem, see Edsall and McKenzie, 1983). In the case of lysozyme, a substantial proportion of the hydrophobic residues Leu, Val, He, Ala, Gly, Phe, Tyr, Trp, Met, and Pro are either fully exposed to solvent or at least have some atoms that are solvent accessible. Examples of hydrophobic residues that are surface exposed are Val-2, Phe-3, Leu-17, Phe-34, Leu-75, Trp-123, Pro-70, and Pro-79, with Trp-62, Trp-63, Ile-98, Trp-108, and Val-109 being on the surface of the cleft. Examples of the least-exposed ionizable side chains are Asp-66, Asp-52, Tyr-53, His-15, and Glu-35. 

---