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 Plus annual

Presents the access of premium content as premium feature

Premium Content

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 annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

A plausible consequence of rugged energy landscapes of biomolecules is thatfunctionally competent folded states may not be unique, as is generallyassumed. Indeed, molecule-to-molecule variations in the dynamics of enzymes andribozymes under folding conditions have recently been identified in singlemolecule experiments. However, systematic quantification and the structuralorigin of the observed complex behavior remain elusive. Even for a relativelysimple case of isomerization dynamics in Holliday Junctions (HJs), molecularheterogeneities persist over a long observation time (Tobs ~ 40 sec). Here,using concepts in glass physics and complementary clustering analysis, weprovide a quantitative method to analyze the smFRET data probing theisomerization in HJ dynamics. We show that ergodicity of HJ dynamics iseffectively broken; as a result, the conformational space of HJs is partitionedinto a folding network of kinetically disconnected clusters. Whileisomerization dynamics in each cluster occurs rapidly as if the associatedconformational space is fully sampled, distinct patterns of time seriesbelonging to different clusters do not interconvert on Tobs. Theory suggeststhat persistent heterogeneity of HJ dynamics is a consequence of internalmultiloops with varying sizes and flexibilities frozen by Mg2+ ions. Anannealing experiment using Mg2+ pulse that changes the Mg2+ cocentration fromhigh to low to high values lends support to this idea by explicitly showingthat interconversions can be driven among trajectories with different patterns.

Hidden Complexity in the Isomerization Dynamics of Holliday Junctions