Identification of Allosteric Fingerprints of Alpha-Synuclein Aggregates in Matrix Metalloprotease-1 and Substrate-Specific Virtual Screening with Single Molecule Insights
Abstract Alpha-synuclein (aSyn) has implications in pathological protein aggregations in neurodegeneration. Matrix metalloproteases (MMPs) are broad-spectrum proteases and cleave aSyn, leading to aggregation. Previously, we showed that allosteric communications between the two domains of MMP1 on collagen fibril and fibrin depend on substrates, activity, and ligands. Here we report quantification of allostery using single molecule measurements of MMP1 dynamics on aSyn-induced aggregates by calculating Forster Resonance Energy Transfer (FRET) between two dyes attached to the catalytic and hemopexin domains of MMP1. The two domains of MMP1 prefer open conformations that are inhibited by a single point mutation E219Q of MMP1 and tetracycline, an MMP inhibitor. A two-state Poisson process describes the interdomain dynamics, where the two states and kinetic rates of interconversion between them are obtained from histograms and autocorrelations of FRET values. Since a crystal structure of aSyn-bound MMP1 is not available, we performed molecular docking of MMP1 with aSyn using ClusPro. We simulated MMP1 dynamics using different docking poses and matched the experimental and simulated interdomain dynamics to identify an appropriate pose. We used experimentally validated simulations to define conformational changes at the catalytic site and identify allosteric residues in the hemopexin domain having strong correlations with the catalytic motif residues. We defined Shannon entropy to quantify MMP1 dynamics. We performed virtual screening against a site on selected aSyn-MMP1 binding poses and showed that lead molecules differ between free MMP1 and substrate-bound MMP1. Also, identifying aSyn-specific allosteric residues in MMP1 enabled further selection of lead molecules. In other words, virtual screening needs to take substrates into account for substrate-specific control of MMP1 activity. Molecular understanding of interactions between MMP1 and aSyn-induced aggregates may open up the possibility of degrading aggregates by targeting MMPs.