Release of linker histone from the nucleosome driven by polyelectrolyte competition with a disordered protein

Pétur O Heidarsson, Davide Mercadante, Andrea Sottini, Daniel Nettels, Madeleine B Borgia, Alessandro Borgia, Sinan Kilic, Beat Fierz, Robert B Best, Benjamin Schuler

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Highly charged intrinsically disordered proteins are essential regulators of chromatin structure and transcriptional activity. Here we identify a surprising mechanism of molecular competition that relies on the pronounced dynamical disorder present in these polyelectrolytes and their complexes. The highly positively charged human linker histone H1.0 (H1) binds to nucleosomes with ultrahigh affinity, implying residence times incompatible with efficient biological regulation. However, we show that the disordered regions of H1 retain their large-amplitude dynamics when bound to the nucleosome, which enables the highly negatively charged and disordered histone chaperone prothymosin α to efficiently invade the H1-nucleosome complex and displace H1 via a competitive substitution mechanism, vastly accelerating H1 dissociation. By integrating experiments and simulations, we establish a molecular model that rationalizes the remarkable kinetics of this process structurally and dynamically. Given the abundance of polyelectrolyte sequences in the nuclear proteome, this mechanism is likely to be widespread in cellular regulation.

Original languageEnglish
JournalNature Chemistry
Volume14
Issue number2
Pages (from-to)224-231
Number of pages8
ISSN1755-4330
DOIs
Publication statusPublished - Feb 2022

Bibliographical note

© 2022. The Author(s), under exclusive licence to Springer Nature Limited.

Keywords

  • Histones/metabolism
  • Humans
  • Intrinsically Disordered Proteins/metabolism
  • Nucleosomes/metabolism
  • Polyelectrolytes/metabolism

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