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Ion counting demonstrates a high electrostatic field generated by the nucleosome.

ABSTRACT: In eukaryotes, a first step towards the nuclear DNA compaction process is the formation of a nucleosome, which is comprised of negatively charged DNA wrapped around a positively charged histone protein octamer. Often, it is assumed that the complexation of the DNA into the nucleosome completely attenuates the DNA charge and hence the electrostatic field generated by the molecule. In contrast, theoretical and computational studies suggest that the nucleosome retains a strong, negative electrostatic field. Despite their fundamental implications for chromatin organization and function, these opposing views of nucleosome electrostatics have not been experimentally tested. Herein, we directly measure nucleosome electrostatics and find that while nucleosome formation reduces the complex charge by half, the nucleosome nevertheless maintains a strong negative electrostatic field. Our studies highlight the importance of considering the polyelectrolyte nature of the nucleosome and its impact on processes ranging from factor binding to DNA compaction.

SUBMITTER: Gebala M

PROVIDER: S-EPMC6584128 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature

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Ion counting demonstrates a high electrostatic field generated by the nucleosome.

Gebala Magdalena M Johnson Stephanie L SL Narlikar Geeta J GJ Herschlag Dan D

eLife 20190611

In eukaryotes, a first step towards the nuclear DNA compaction process is the formation of a nucleosome, which is comprised of negatively charged DNA wrapped around a positively charged histone protein octamer. Often, it is assumed that the complexation of the DNA into the nucleosome completely attenuates the DNA charge and hence the electrostatic field generated by the molecule. In contrast, theoretical and computational studies suggest that the nucleosome retains a strong, negative electrostat ...[more]

PMID: 31184587

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Ion counting demonstrates a high electrostatic field generated by the nucleosome.

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Ion counting demonstrates a high electrostatic field generated by the nucleosome.

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