Lysozyme synthetic antigenic sites

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. 

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).

A third antigenic site has been identified in hen egg-white lysozyme using a synthetic surface-simulation approach, which reveals contributions from residues that are close to the site in the three-dimension2il structure although distant from it in the amino-acid sequence. It appears that the antigenic site need not always include residues that are in direct peptide linkage. 

Enzymes.—Peptides related to some of the sequences of hen egg-white lysozyme have been synthesized to aid in identifying the antigenic sites of the enzyme. " A semi-synthetic approach to fragments of hen egg-white lysozyme has been de-... 

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. 

Several surface-simulation synthetic peptides have been synthesized in order to investigate the conformation restrictions of the antigenic site of hen egg-white lysozyme and to determine if the spatially constructed antigenic site has a preferred direction . The results from interaction direct and via immuno-adsorption showed that the peptide (IS) possessed the maximum inhibitory... 

Fig. 9,2. The antigenic sites of hen egg white lysozyme and the corresponding synthetic peptides used in the method of surface simulation synthesis (from Atassi and Lee, 1978b).

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