Electrochemical flow injection analysis of the interaction between pyrroloquinoline quinone (PQQ) and α-synuclein peptides related to Parkinson's disease. Issue 14 (18th June 2021)

• Record Type: Journal Article
• Authors: Li, Shaopei; Noroozifar, Meissam; Zhou, Jiayun; Kerman, Kagan
• Is Part Of: Analyst. Volume 146:Issue 14(2021)
• Page Start: 4545
• Page End: 4556
• Publication Date: 2021-06-18
• Subjects: Chemistry, Analytic -- Periodicals; 543
• DOI: 10.1039/d1an00698c
• Languages: English
• ISSNs: 0003-2654

Abstract

Abstract : An electrochemical flow cell system was constructed to study the biomolecular interactions of α-synuclein (α-syn) peptides with pyrroloquinoline quinone (PQQ) and copper(ii ). Abstract : α-Synuclein (α-syn) is a hallmark protein of Parkinson's disease (PD). The aggregation process of α-syn has been heavily associated with the pathogenesis of PD. With the exponentially growing number of potential therapeutic compounds that can inhibit the aggregation of α-syn, there is now a significant demand for a high-throughput analysis system. Herein, a novel flow injection analysis system with an electrochemical biosensor as the detector was developed to study the interaction of a well-described antioxidant and amyloid inhibitor, pyrroloquinoline quinone (PQQ) with α-synuclein peptides. Screen-printed gold electrodes (SPEs) were modified using heptapeptides from α-syn wild-type (WT) and mutants such as lysine knock-out (ETEE) and E46K. Affinity binding events between these peptides and PQQ were analyzed by electrochemical impedance spectroscopy (EIS) and further confirmed by high-performance liquid chromatography (HPLC), liquid chromatography/mass spectrometry (LC/MS), and nuclear magnetic resonance (NMR) spectroscopy. HPLC and LC/MS results revealed that PQQ formed a stable complex with α-syn. NMR results confirmed that the α-syn–PQQ complex was formed via a Schiff base formation-like process. In addition, results showed that lysine residues influenced the binding event, in which the presence of an extra lysine stabilized the α-syn–PQQ complex, and the absence of a lysine significantly decreased the interaction of α-syn with PQQ. Therefore, we concluded that EIS is a promising technique for the evaluation of the interaction between PQQ-based amyloid inhibitors and α-syn. The electrochemical flow injection analysis assembly provided a rapid and low-cost drug discovery platform for the evaluation of small molecule–protein interactions.