Model proteins hydrophobicity

The most direct observation of changes in hydrophobic hydration attending the inverse temperature transition comes from following the temperature dependence of an absorption band in the microwave dielectric relaxation experiment shown in Figures 5.24 and 5.25. The water of hydrophobic hydration, with an absorption band near 5 GHz in the dissolved model protein, disappears on raising the temperature through the inverse temperature transition as the model protein hydrophobically... 

Lau, S. Y. M., Taneja, A. K., and Hodges, R. S., Effects of high-performance liquid chromatographic solvents and hydrophobic matrices on the secondary and quaternary structure of a model protein. Reversed-phase and size exclusion high-performance liquid chromatography, /. Chromatogr., 317, 129, 1984. 

DW Urry, SQ Peng, TM Parker, DC Gowda, RD Harris. Relative significance of electrostatic-induced and hydrophobic-induced pKa shifts in a model protein—The aspartic acid residue. Angew Chem Int Ed 32 1440-1442, 1993. 

Hummer, G., Garde, S., Garcia, A. E., Paulaitis, M. E., and Pratt, L. R. (1998b). The pressure dependence of hydrophobic interactions is consistent with the observed pressure denaturation of proteins. Proc. Natl. Acad. Sci. USA 95, 1552-1555. Hummer, G., Garde, S., Garcia, A. E., Pohorille, A., and Pratt, L. R. (1996). An information theory model of hydrophobic interactions. Proc. Natl. Acad. Sci. USA 93, 8951-8955. 

Proteins may be stabilized by encapsulation in polyanhydride microspheres. Stability of proteins with respect to water-induced aggregation has been demonstrated to be a function of polymer hydrophobicity for insulin and bovine somatotropin as model proteins (Ron et al., 1993). Encapsulation and enzymatic activity of a variety of other proteins encapsulated in P(SA FAD) was studied by Tabata et al. (1993). 

Optimal rates of folding occur when there is not an initial collapse of structure, hydrophobic or otherwise, but when there is a specific and extended nucleus in the transition state model proteins evolve toward nucleation mechanisms with extended nuclei.45,47... 

Some attention should be also paid to the fact that some copolymers with special sequence distribution do not assume cylindrical shape within the HA model. For example, this is the case for protein-like sequences. Protein-like sequences correspond to a copolymer which forms globules with a hydrophobic core and a hydrophilic shell showing no tendency to aggregation. Proteinlike copolymers have been previously studied within the HP model [32-34], Application of the more realistic HA model showed that the globules formed by protein-like copolymers under worsening solvent quality assume conventional spherical shape and show no tendency to aggregate [23]. The stability for HA model protein-like copolymers is much higher than for those within the HP model. 

In addition to the use of micelles as models for hydrophobic interactions in protein systems, information concerning the dilferent binding sites of protein molecules can be obtained by studying the elFects of surfactants on the properties of proteins and related compounds. The ensuing discussion is centered on these two applications of amphiphilic systems. 

The phenomenon of viral adsorption to various surfaces was extensively studied from an environmental standpoint as reviewed by Daniels (14) and Gerba (15) for prevention of various waterborne viral transmissions. The problem of virus removal from complex protein solutions is very different from that of sewage and drinking water treatment processes because most protein molecules compete for the active sites of the adsorbents. Hence, both the adsorption rate and capacity diminish in the presence of protein molecules (16). It is the intention of this paper to demonstrate and to compare the antiviral activity of a surface-bonded QAC in aqueous solutions against 2 model viruses with and without the presence of proteins. The efficacy of the accepted antiviral thermo-inactivation was compared with the viral inactivation method by the surface-bonded QAC treatment. Beta-lactamase was used as a thermolabile model protein (17), and bacteriophage T2 and herpes simplex virus type 1 (HSV-1, an enveloped animal virus) were used as model hydrophilic and hydrophobic viruses to test these chemical inactivation methods. 

Jackson, R. M. Sternberg, M. J. E. (1994). Application of scaled particle theory to model the hydrophobic effect implications for molecular association and protein stability. Prot. Eng. 7, 371-383. 

For the construction of artificial metalloproteins, protein scaffolds should be stable, both over a wide range of pH and organic solvents, and at high temperature. In addition, crystal structures of protein scaffolds are crucial for their rational design. The proteins reported so far for the conjugation of metal complexes are listed in Fig. 1. Lysozyme (Ly) is a small enzyme that catalyzes hydrolysis of polysaccharides and is well known as a protein easily crystallized (Fig. la). Thus, lysozyme has been used as a model protein for studying interactions between metal compounds and proteins [13,14,42,43]. For example, [Ru(p-cymene)] L [Mn(CO)3l, and cisplatin are regiospecificaUy coordinated to the N = atom of His 15 in hen egg white lysozyme [14, 42, 43]. Serum albumin (SA) is one of the most abundant blood proteins, and exhibits an ability to accommodate a variety of hydrophobic compounds such as fatty acids, bilirubin, and hemin (Fig. lb). Thus, SA has been used to bind several metal complexes such as Rh(acac)(CO)2, Fe- and Mn-corroles, and Cu-phthalocyanine and the composites applied to asymmetric catalytic reactions [20, 28-30]. 

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