Identification of Substrate-specific Allosteric Fingerprints in Matrix Metalloprotease-1 on Amyloid-beta Peptide Aggregates and Drug Screening With Single Molecule Insights

Amyloid-beta peptide (Aβ) is the primary component of water-insoluble extracellular plaques, one of the critical hallmarks of Alzheimer's disease (AD). Matrix metalloproteases (MMPs) are broad-spectrum proteases with diverse functions, including interactions with Aβ. Here we report single molecule measurements of MMP1 dynamics on Aβ-induced aggregates by calculating Forster Resonance Energy Transfer (FRET) between two dyes attached to the catalytic and hemopexin domains. We show that the two domains of MMP1 prefer closed conformations on Aβ-induced aggregates, in contrast to the preference for open conformations on collagen fibril, fibrin, and alpha-synuclein aggregates. We approximated the MMP1 dynamics by a two-state Poisson process and determined the kinetic rates of interconversion between the two states from histograms and correlations of FRET values. We performed molecular docking of MMP1 with Aβ using ClusPro, simulated MMP1 dynamics using different docking poses, and matched the experimental and simulated interdomain dynamics to identify an appropriate pose. We used simulations to create a two-dimensional map of correlations between every pair of MMP1 residues, which shows allosteric communications between the two MMP1 domains. We calculated a Gray Level Co-occurrence Matrix from the two-dimensional map of correlations and quantified MMP1 fluctuations by Shannon entropy. We identified the allosteric residues in the hemopexin domain by identifying residues having strong correlations with the catalytic motif residues. We identified that the residues I364, G369, P409, G410, and D418 in MMP1 have Aβ-specific allosteric correlations with the MMP1 catalytic motif by comparing residues for free and Aβ-bound MMP1. We used these Aβ-specific allosteric residues to select small molecule ligands after the virtual screening of molecules against Aβ-bound MMP1. Molecular understanding of interactions between MMP1 and Aβ-induced aggregates and identification of substrate-specific allosteric residues may enable controlling MMP1 function selectively on Aβ.