Influence of Fluorination on Single-Molecule Unfolding and Rupture Pathways of a Mechanostable Protein Adhesion Complex
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Date
2020-12-09
Publication Type
Journal Article
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yes
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Abstract
We investigated the influence of fluorination on unfolding and unbinding reaction pathways of a mechanostable protein complex comprising the tandem dyad XModule-Dockerin bound to Cohesin. Using single-molecule atomic force spectroscopy, we mapped the energy landscapes governing the unfolding and unbinding reactions. We then used sense codon suppression to substitute trifluoroleucine in place of canonical leucine globally in XMod-Doc. Although TFL substitution thermally destabilized XMod-Doc, it had little effect on XMod-Doc:Coh binding affinity at equilibrium. When we mechanically dissociated global TFL-substituted XMod-Doc from Coh, we observed the emergence of a new unbinding pathway with a lower energy barrier. Counterintuitively, when fluorination was restricted to Doc, we observed mechano-stabilization of the non-fluorinated neighboring XMod domain. This suggests that intramolecular deformation is modulated by fluorination and highlights the differences between equilibrium thermostability and non-equilibrium mechanostability. Future work is poised to investigate fluorination as a means to modulate mechanical properties of synthetic proteins and hydrogels.
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published
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Book title
Journal / series
Volume
20 (12)
Pages / Article No.
8940 - 8950
Publisher
American Chemical Society
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Date collected
Date created
Subject
Atomic force microscopy; Single-molecule force spectroscopy; Protein engineering; Fluorine; Elastin-like polypeptide; SpyTag/SpyCatcher; Molecular deformation
Organisational unit
09586 - Nash, Michael / Nash, Michael