The precise and entire antigenic structure of native lysozyme.
Ontology highlight
ABSTRACT:
SUBMITTER: Atassi MZ
PROVIDER: S-EPMC1183972 | biostudies-other | 1978 May
REPOSITORIES: biostudies-other
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Project description:Previously it had been shown that native lysozyme has three discontinuous antigenic sites (comprising spatially adjacent residues that may be distant in sequence) that were mimicked by surface-simulation synthetic peptides that had the capacity to bind the bulk (97-99%) of the antibody response against native lysozyme. In the present work these three surface-simulation synthetic peptides were coupled to succinoylated bovine serum albumin, and the conjugates were injected into rabbits. Antibodies against each peptide reacted, as expected, only with that peptide, but it was also found that the antibodies could bind with lysozyme, and the complete specificity of this binding was rigorously established. The advantages of these findings in conformational and immunological investigations are outlined.
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Project description:Epigallocatechin gallate (EGCG), the most abundant flavanoid in green tea, is currently being evaluated in the clinic due to its benefits in the treatment of amyloid disorders. Its anti-amyloidogenic effect has been attributed to direct interaction of the intact molecule with misfolded polypeptides. In addition, antioxidant activity is also involved in the anti-amyloidogenic role. The detailed molecular mechanism is still unclear and requires further investigation. In the present study, the kinetics of EGCG oxidation and the anti-amyloidogenic effect of the resultant oxidation substances have been examined. The results indicate that EGCG degrades in a medium at pH 8.0 with a half-life less than 2h. By utilizing lysozyme as an in vitro model, the oxidized EGCG demonstrates a more potent anti-amyloidogenic capacity than the intact molecule, as shown by ThT and ANS fluorescence, TEM determination, and hemolytic assay. The oxidized EGCG also has a stronger disruptive effect on preformed fibrils than the native form. Ascorbic acid eliminates the disruptive role of native EGCG on the fibrils, suggesting that oxidation is a prerequisite in fibril disruption. The results of this work demonstrate that oxidized EGCG plays a more important role than the intact molecule in anti-amyloidogenic activity. These insights into the action of EGCG may provide a novel route to understand the anti-amyloidogenic activity of natural polyphenols.
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