Binding between Different Types of Oligopeptide-AGEs and the V Domain of RAGE: Modulation by Lotus Seedpod Oligomeric Procyanidins

During food processing, the Maillard reaction generates advanced glycation end-products (AGEs), which are absorbed as oligopeptide-AGEs (OLP-AGEs) and bind with extracellular domain V of the receptor for AGEs (RAGE-V), inducing physiological toxicity. However, the associative feature of binding of the OLP-AGEs to RAGE-V is not yet clear. This study prepared OLP-AGEs from casein and synthesized RAGE-V using <i><i>Escherichia coli</i></i>. Binding assays revealed the following order: GO-glycated OLP (90.07 ± 0.04%) > lactose-glycated OLP (69.70 ± 0.56%) > heat-treated OLP (30.59 ± 1.11%) > untreated (5.19) OLP (5.91 ± 1.96%). After conducting a correlation analysis of various indicators, the results indicated a significant correlation between the binding of OLP-AGEs and the RAGE-V structural domain with amino acid content, sulfhydryl group content, β-cross structure content, and negative potential. Preliminary studies on the inhibitory effect of lotus seedpod oligomeric procyanidins (LSOPCs) on OLP-AGEs demonstrated that LSOPC could partially inhibit the binding between OLP-AGEs and RAGE-V. After adding LSOPC, the binding rates of each group were GO-glycated OLP (85.56 ± 0.48%), lactose-glycated OLP (24.92 ± 1.61%), heat-created OLP (7.98 ± 0.45%), and uncreated OLP (4.67 ± 1.53%). These findings establish the structural basis for OLP-AGEs-RAGE-V interactions, aiding strategies to mitigate dietary AGEs toxicity.