English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Single molecule force spectroscopy methods can be used to generate foldingtrajectories of biopolymers from arbitrary regions of the folding landscape. Weillustrate the complexity of the folding kinetics and generic aspects of thecollapse of RNA and proteins upon force quench, using simulations of an RNAhairpin and theory based on the de Gennes model for homopolymer collapse. Thefolding time, $\tau_F$, depends asymmetrically on $\delta f_S = f_S - f_m$ and$\delta f_Q = f_m - f_Q$ where $f_S$ ($f_Q$) is the stretch (quench) force, and$f_m$ is the transition mid-force of the RNA hairpin. In accord withexperiments, the relaxation kinetics of the molecular extension, $R(t)$, occursin three stages: a rapid initial decrease in the extension is followed by aplateau, and finally an abrupt reduction in $R(t)$ that occurs as the nativestate is approached.  The duration of the plateau increases as $\lambda =\tau_Q/\tau_F$ decreases(where $\tau_Q$ is the time in which the force is reduced from $f_S$ to $f_Q$).Variations in the mechanisms of force quench relaxation as $\lambda$ is alteredare reflected in the experimentally measurable time-dependent entropy, which iscomputed directly from the folding trajectories. An analytical solution of thede Gennes model under tension reproduces the multistage stage kinetics in$R(t)$. The prediction that the initial stages of collapse should also be ageneric feature of polymers is validated by simulation of the kinetics oftoroid (globule) formation in semiflexible (flexible) homopolymers in poorsolvents upon quenching the force from a fully stretched state. Our findingsgive a unified explanation for multiple disparate experimental observations ofprotein folding.

Refolding dynamics of stretched biopolymers upon force quench