title: Thermal Unthreading of the Lasso Peptides Astexin-2 and Astexin-3.
abstract: Lasso peptides are a class of knot-like polypeptides in which the C-terminal tail of the peptide threads through a ring formed by an isopeptide bond between the N-terminal amine group and a side chain carboxylic acid. The small size (∼20 amino acids) and simple topology of lasso peptides make them a good model system for studying the unthreading of entangled polypeptides, both with experiments and atomistic simulation. Here, we present an in-depth study of the thermal unthreading behavior of two lasso peptides astexin-2 and astexin-3. Quantitative kinetics and energetics of the unthreading process were determined for variants of these peptides using a series of chromatography and mass spectrometry experiments and biased molecular dynamics (MD) simulations. In addition, we show that the Tyr15Phe variant of astexin-3 unthreads via an unprecedented "tail pulling" mechanism. MD simulations on a model ring-thread system coupled with machine learning approaches also led to the discovery of physicochemical descriptors most important for peptide unthreading.
authors: Departments of Chemical and Biological Engineering and ‡Molecular Biology, Princeton University , Princeton, New Jersey 08544, United States.|Department of Materials Science and Engineering and ∥Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
authors: Caitlin D
authors: CD
authors: Allen
authors: Departments of Chemical and Biological Engineering and ‡Molecular Biology, Princeton University , Princeton, New Jersey 08544, United States.|Department of Materials Science and Engineering and ∥Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
authors: Maria Y
authors: MY
authors: Chen
authors: Departments of Chemical and Biological Engineering and ‡Molecular Biology, Princeton University , Princeton, New Jersey 08544, United States.|Department of Materials Science and Engineering and ∥Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
authors: Alexander Y
authors: AY
authors: Trick
authors: Departments of Chemical and Biological Engineering and ‡Molecular Biology, Princeton University , Princeton, New Jersey 08544, United States.|Department of Materials Science and Engineering and ∥Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
authors: Dan Thanh
authors: DT
authors: Le
authors: Departments of Chemical and Biological Engineering and ‡Molecular Biology, Princeton University , Princeton, New Jersey 08544, United States.|Department of Materials Science and Engineering and ∥Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
authors: Andrew L
authors: AL
authors: Ferguson
authors: Departments of Chemical and Biological Engineering and ‡Molecular Biology, Princeton University , Princeton, New Jersey 08544, United States.|Department of Materials Science and Engineering and ∥Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
authors: A James
authors: AJ
authors: Link
mesh_terms: D007700:Kinetics; D056004:Molecular Dynamics Simulation; D010455:Peptides / Q000737:chemistry*; D055550:Protein Stability
chemical_list: D010455:Peptides