Alpha-synuclein fibril conformational epitope

The alpha-synuclein fibril conformational epitope is a structurally defined surface region exposed in alpha-synuclein fibrils or pathogenic aggregates, but shielded or conformationally inaccessible in the native, monomeric form. The most studied epitope region is "EKTKEQ" (residues 57–62), identified by bioinformatics methods measuring increased solvent accessibility and local structural disorder within misfolded fibrillar forms[1]. This conformational epitope is being selectively targeted by antibodies and peptide vaccines aiming to neutralize pathogenic aggregates in synucleinopathies (such as Parkinson’s disease) without affecting the physiological monomeric protein[1][2][5]. Multiple studies have designed cyclic peptide scaffolds mimicking this epitope to generate conformation-selective antibodies, with experimental evidence showing antibody binding and impact on cellular models of disease[1][2][5]. The precise location and structure of the exposed epitope can vary depending on alpha-synuclein fibril polymorphs, which may affect antibody specificity and therapeutic efficacy[3][5]. The "target" is a specific conformation-dependent epitope (e.g., a stretch of exposed residues) present in misfolded alpha-synuclein aggregates (fibrils), not in its native folded or disordered state. This target is distinct from the alpha-synuclein protein itself, as only the aggregated, disease-associated form presents the epitope[1][2][5]. This epitope is under development as a precision immunotherapy target, and not a traditional endogenous receptor, enzyme, or ion channel[1][2]. The most widely validated epitope for antibody/vaccine targeting is EKTKEQ (residues 57–62), but other regions around amino acids 32–58 or C-terminus regions may also form disease-associated conformational epitopes[1][2].

Other names

Alpha-synuclein aggregate conformational epitopeAlpha-synuclein fibrillar epitopeAlpha-synuclein misfolding-specific conformational epitope

Selective antibody binding to fibrillar/aggregated alpha-synuclein (blocks propagation or facilitates clearance). Immunotherapy: antibody or vaccine targets epitope exposed only in pathogenic fibril, sparing monomer.