1. Selection of mutant µplasmin for amyloid-β cleavage in vivo.
- Author
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Yang D, Zhu W, Wang Y, Tan F, Ma Z, Gao J, and Lin X
- Subjects
- Animals, Binding Sites, Catalytic Domain, Humans, Mice, Models, Molecular, Molecular Dynamics Simulation, Peptide Fragments genetics, Peptide Fragments metabolism, Plasminogen genetics, Plasminogen metabolism, Protein Conformation, Amyloid beta-Peptides metabolism, Mutation, Peptide Fragments chemistry, Plasminogen chemistry, alpha-2-Antiplasmin metabolism
- Abstract
One of the main culprits of Alzheimer's disease (AD) is the formation of toxic amyloid-β (Aβ) peptide polymers and the aggregation of Aβ to form plaques in the brain. We have developed techniques to purify the catalytic domain of plasmin, micro-plasmin (µPlm), which can be used for an Aβ-clearance based AD therapy. However, in serum, µPlm is irreversibly inhibited by its principal inhibitor α2-antiplasmin (α2-AP). In this study, we engineered and selected mutant forms of µPlm that are both catalytically active and insensitive to α2-AP inhibition. We identified surface residues of μPlm that might interact and bind α2-AP, and used an alanine-scanning mutagenesis method to select residues having higher activity but lower α2-AP inhibition. Then we employed saturation mutagenesis for further optimize both properties. Modeled complex structure of µPlm/α2-AP shows that F587 is a critical contact residue, which can be used as a starting position for further investigation.
- Published
- 2020
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