Chicken egg white lysozyme

Figure 12.9 MALDI-TOF mass spectrum of chicken egg-white lysozyme. The peak at 14,307.7578 daltons (amu) is due to the monoprotonated protein, M+H+, and that at 28,614.2188 daltons is due to an impurity formed by dimerization of the protein. Other peaks are various protonated species, M+H rH ...

The AB + C case is illustrated by the works of Kabanov et al. [296], who investigated mixtures of PEO-PMANa with P4VPQ, of Gohy et al. on the pH-dependent complexation of P2VP-PEO with PSS [297,298], and of Kataoka and coworkers on PEO-PAspA/chicken egg white lysozyme mixtures [299, 300]. In all these studies, the resulting micelles contained an IPEC core and a PEO corona. 

Figure 4.2. GenBank format for nucleotide sequence of chicken egg-white lysozyme.

The bird lysozymes c, of which chicken egg white lysozyme (CL) is the most extensively studied example, provide an ideal system to recreate evolutionary intermediates and to study structure-function relationships of reconstructed ancestral proteins. Three major considerations qualify the avian lysozyme system for reconstruction of evolutionary pathways (1) the biochemistry of the enzymes has been extensively studied and well characterized,3,4 (2) there are many natural variants available from other birds, and homologous comparisons can be ensured since lysozymes for all game birds are encoded by a single gene,5 and (3) the three-dimensional structure of CL has been resolved at the atomic level, which allows for structural interpretation of the mutational impact.2,4 Proteins representing the ancestral, evolutionarily intermediate, and derived states of chicken and related bird lysozymes are made and characterized as described below. 

The CL variants are constructed by site-directed mutagenesis of the cDNA for chicken egg white lysozyme and heterologously expressed in yeast behind a regulated hybrid promoter.6... 

Fio. 2. Subcloning and expression system for chicken egg white lysozyme. See the text (section on subcloning) for further details. RF, Replicative form. 

Chicken egg white lysozyme (LZM) does not possess exposed methionyl residues, and it has six tryptophan residues, three of which, located at positions 62,108, and 111 are readily oxidizable with ozone and are built-in the LZM active center (D14). Tryptophanyl residues are also the first reacting moieties upon treatment of LZM with the MPO-Cr-H2C>2 system (at pH 4.5). The reaction occurs in several stages. In the first stage, which occurs when 1.4-1.8 mol of H2O2 for 1 mol of LZM is used, LZM loses its enzyme activity, but no derivative distinguishable from the native protein on the polyacrylamide gel electrophoresis is formed. The inactivation may be prevented by addition to the reaction medium A-acetylcysteine or... 

Figure 4 The electrostatic distributions of a-lactalbumin (lALC) (a) and chicken egg-white lysozyme (ILZl) (b) calculated by Delphi and presented by Grasp. Both surfaces of calcium-binding protein a-lactalbumin are mostly negatively charged (a) (in red) while the surfaces of noncalcium binding protein lysozyme (b) are mostly positively charged (in blue)...

E.L. Forsythe, R.A. Judge, M.L. Pusey, Tetragonal chicken egg white lysozyme solubility in sodium chloride solutions, J. Chem. Eng. Data 44(1999) 637-640. 

Proteolytic activity of BO, BO °", BP, and BP was examined by using horse heart myoglobin, bovine serum y-globulin, BSA, human serum albumin, chicken egg white lysozyme, and chicken egg ovalbumin as the substrates. Examples of the kinetic data are illustrated in Fig. 2. The values of K, and for the cleavage of the protein substrates by BO, BO °", BP, and BP... 

A FIGURE 3-15 Antibody structure and antibody-antigen interaction, (a) Ribbon model of an antibody. Every antibody molecule consists of two identical heavy chains (red) and two identical light chains (blue) covalently linked by disulfide bonds, (b) The hand-in-glove fit between an antibody and an epitope on its antigen—in this case, chicken egg-white lysozyme. Regions... 

The primary structure of a-la is shown in Figure 4.25. There is considerable homology between the sequence of a-la and lysozymes from many sources. The primary structures of a-la and chicken egg white lysozyme are very similar. Out of a total of 123 residues in a-la, 54 are identical to corresponding residues in lysozyme and a further 23 residues are structurally similar (e.g. Ser/Thr, Asp/Glu). 

PIR (upper), Swiss-Prot (middle) and GenPept (lower) formats for amino acid sequence of chicken egg-white lysozyme are represented. Swiss-Prot format is the default format of EMBL/EBI and GenPept format is the default format adopted by GenBank (Entrez) and DDBJ (DBGet). Pasta format is shown in subsection 5.1.2. 

The TOF technique is considerably more sensitive than the magnetic-sector alternative, and protein samples of up to 100 kilodaltons (100,000 amu) can be separated with a mass accuracy of 3 ppm. Figure 10.9 shows a MALDI-TOF spectrum of chicken egg-white lysozyme, MW = 14,306.7578 daltons. (Biochemists generally use the unit dalton, abbreviated Da, instead of amu.)... 

FIGURE 3.10 ESI-MS of proteins. Chicken egg white lysozyme in the absence (top) and presence (middle) of dithiothreitol. (From Gross, J. H., Mass Spectrometry A Textbook, Spinger, Berlin, 2004. Reprinted with permission.)... 

Bradshaw, R. A., and D. A. T)eranleau Use of N-methylnicotinamide Chloride as a Conformational Probe in Proteins. Identification of the Binding Sites in Chicken Egg-white Lysozyme and a Comparison with Bovine a-Lactalbumin. Biochemistry 9, 3310-3315 (1970). 

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