Lysozyme molecular properties

In order to elucidate relationships between surface active and film forming properties of food proteins, it is useful to examine the surface active properties of proteins whose physical and molecular properties are well characterized e.g. -casein, bovine serum albumin (BSA), lysozyme ( ), and -lactoglobulin (b-Lg) (2jL). These represent a range of tertiary structures for soluble proteins. Lysozyme is a rigid and roughly ellipsoidal molecule, whereas the hydrophobic -casein molecule is mostly a random coil structure. The b-Lg molecule consists almost entirely of antiparallel -sheet strands organized into a flattened cone ( ). 

S. Melino, M. Zhou, M. Tortora, M. Paci, F. Cavalieri, M. Ashokkumar, Molecular properties of lysozyme-microbubbles towards the protein and nucleic acid delivery. Amino Acids 43, 885-896 (2012)... 

The model systems, discussed here, contain one type of well-defined protein and one type of well-characterized solid surface in an aqueous medium containing one type of low molecular-weight electrolyte. Table 2 summarizes some relevant properties of the proteins. Lysozyme (LSZ)... 

With tree analysis it is possible to infer sequences of ancestral proteins and probable evolutionary pathways to their modern descendants.1 The advent of site-directed mutagenesis makes possible the recreation of evolutionary intermediates based on these predictions. One may then compare the properties of reconstructed intermediates with one another and with proteins from contemporary creatures. These comparisons provide a way of testing theories about the mechanism of molecular evolution. For example, this approach has provided a new criterion for distinguishing between neutral and nonneutral events.2 This chapter describes the use of site-directed mutagenesis to recreate ancestral lysozymes and presents methods of evaluating their properties. 

In 1958 Yasunobu and Wilcox drew attention to certain similarities between a-lactalbumin and lysozyme (see Gordon, 1971). A few years later Brew and Campbell (1967) also drew attention to their marked similarity in molecular weights, amino acid composition, and the amino-and carboxy-terminal amino acid residues. They stated, To the extent that the properties mentioned reflect similar primary structures, the a-lactalbumins may have evolved by gradual modification from lysozyme, which is found in the milk of many species (p. 263). This proposal prompted Brew etal. (1967, 1970) to determine the amino acid sequence of bovine a-lactalbumin, which proved to have a high level of sequence identity with domestic hen egg-white lysozyme. Thus, these studies were in accordance with the proposal that the two proteins had diverged from a common ancestor (see also Hill etal., 1969, 1974). They stated that although lysozyme does not participate in lactose synthesis and a-lactalbu-... 

Smith, P., R. Brunne, A. Mark and W. vanGunsteren. (1993). Dielectric properties of trypsin inhibitor and lysozyme calculated from molecular dynamics simulations. Journal of Physical Chemistry. 97 2009-2014. 

Total internal reflection intrinsic fluorescence (TIRIF) spectroscopy and molecular graphics have been applied to study the adsorption behavior of two lysozymes on a set of three model surfaces. A recently devised TIRIF quantitation scheme was used to determine adsorption isotherms of both hen egg-white lysozyme (HEWL) and human milk lysozyme on the three model surfaces. This preliminary study suggests that the adsorption properties of the two lysozymes are significantly different, and that further comparative studies of the two lysozymes might prove to be beneficial in understanding how protein structure might influence adsorption properties. Molecular graphics was used to rationalize the adsorption results from TIRIF in terms of the proteins surface hydrophobic/hydrophillic character. 

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