Effects of Site-Specific Glycation on α-Synuclein

Area of Science:

• Biochemistry
• Neuroscience
• Chemical Biology

Background:

• Glycation of alpha-synuclein (αSyn) by methylglyoxal (MGO) is implicated in Parkinson's disease pathogenesis.
• Understanding MGO's role is hindered by the heterogeneity of chemically modified αSyn.

Purpose of the Study:

• To develop site-specific semisynthetic methods for incorporating Nε-carboxyethyllysine (CEL), an MGO adduct, into αSyn.
• To investigate the functional and aggregation consequences of defined CEL modifications on αSyn.

Main Methods:

• Utilized native chemical ligation to create 11 αSyn variants with site-specific CEL modifications.
• Assessed membrane interactions, oligomerization, fibril formation, and seeding capacity using biophysical techniques (DLS, ThT, sedimentation).

Main Results:

• Single CEL modifications did not disrupt αSyn's disordered structure but reduced membrane-induced folding.
• CEL incorporation stabilized small oligomers and attenuated fibril formation, altering aggregate morphology.
• Site-specific CEL modifications reduced αSyn seeding capacity, with K10CEL being an exception.

Conclusions:

• Site-specific glycation by CEL efficiently modulates αSyn aggregation and function.
• The developed semisynthetic platform allows detailed study of MGO-induced glycation effects on αSyn.
• This approach provides a framework for investigating advanced glycation endproducts (AGEs) in synucleinopathies.