Antigenic structure of lysozyme

The highlights of the antigenic structure of lysozyme are outlined here. Native lysozyme has three antigenic sites (4). 

In spite of the aforementioned points of resemblance between the antigenic structures of Mb and lysozyme, the antigenic sites of these two proteins are radically different In structural terms (4). The five antigenic sites of Mb are each made up of residues tTTat are directly linked to one another by peptide bonds (U. 

Fig. 15. Three antigenic sites of lysozyme. The diagram shows the spatially adjacent residues constituting each antigenic site and their numerical positions in the primary structure. The distances separating the consecutive residues and the overall dimension of each site (in its extended form) are given, together with the dimension of each surface-simulation" synthetic site. The latter assumes an ideal C -to-C distance of 0.362 nm. From M. Z. Atassi and C.-L. Lee, Biochem. J. 171, 429 (1978).

Although the last decade has witnessed a great deal of activity investigating the immunochemistry of protein antigens, so far the antigenic structure of sperm whale myoglobin and of lysozyme have been completed. ... 

Atassi MZ (1977) The complete antigenic structure of myoglobin. In Atassi MZ (ed) Immunochemistry of proteins, vol II. Plenum, New York Atassi MZ, Habeeb AFSA (1977) The antigenic structure of hen eggwhite lysozyme A model for disulfide-containing proteins. In Atassi MZ (ed) Immunochemistry of proteins, vol II. Plenum, New York... 

Modification of protein side chains has not been extensively employed in studies of functional sites, and, where it has been used, little has been done to characterize the nature of the products by either chemical or physical methods. This approach, used in its fullest capacity to delineate the complete antigenic structures of sperm whale myoglobin (Atassi, 1975) and lysozyme (Atassi et al., 1976a,b Lee and Atassi, 1977a,b Atassi and Lee, 1978, Atassi, 1978), could be of great value... 

The Antigenic Structure of Hen Egg-White Lysozyme A Model for Disulfide-Containing Proteins... 

The exact boundary, residue, conformational, and directional definitions of the three antigenic sites of hen egg-white lysozyme have been described. The results revealed that the three antigenic sites account quantitatively for the total antigenic reactivity of the protein. Thus the entire antigenic structure of the enzyme has now been determined precisely. Its nature was discussed together with the power of the surface-simulation synthetic concept. 

Radian, E.A., et al. 5tructure of an antibody-antigen complex. Crystal structure of the HyHEL-10 Fab-lysozyme complex. Proc. Natl. Acad. Sci. USA 86 5938-5942,... 

This article focuses mainly on the Immunology of proteins whose complete antigenic structures have been chemically localized and synthetically confirmed. These are Mb, lysozyme, Hb and serum albumin. The antigenic sites of many other proteins are now being Investigated. 

In this exercise you will examine the interactions between the enzyme lysozyme (Chapter 4) and the Fab portion of the anti-lysozyme antibody. Use the PDB identifier 1FDL to explore the structure of the IgGl Fab fragment-lysozyme complex (antibody-antigen complex). View the structure using Protein Explorer, and also use the information in the PDBsum summary of the structure to answer the following questions. 

Mariuzza RA (1996) Crystal structure of the complex of the variable domain of antibody D1.3 and the turkey egg with lysozyme a novel conformational change in antibody CDF-L3 selects for antigen, J Mol Biol, 257 889-894... 

The study by Determan et al. [224] focuses on the effects of polymer degradation products on the primary, secondary, and tertiary structure of TT, OVA, and lysozyme after incubation for 0 or 20 days in the presence of ester (lactic acid and glycolic acid) and anhydride [sebacic acid and l,6-bis(p-carboxyphenoxy)hexane] monomers. The structure and antigenicity or enzymatic activity of each protein in the presence of each monomer was quantified. SDS-PAGE, circular dichroism, and fluorescence spectroscopy were used to assess/evaluate the primary, secondary, and tertiary structures of the proteins, respectively. ELISA was used to measure changes in the antigenicity of TT and OVA and a fluorescence-based assay was used to determine the enzymatic activity of lysozyme. TT toxoid was found to be the most stable in the presence of anhydride monomers, while OVA was most stable in the... 

The challenge of how to represent the receptor that is deduced from these results is greatly helped by the use of computer graphics systems. For example, it was used to show the complementarity of molecular surfaces in the crystal structure of the complex between an antibody and lysozyme. The contact area is about 20x20 A. Side chains from one, such as Gin 121 of lysozyme, fit in a depression on the surface of the other protein. Interactions with small antigens, such as phosphorylcholine, have also demonstrated the specificity of the interactions between antibodies and antigens. 

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