HMGB1 B-Box Domain Associates Promote Protein–Polyelectrolyte Interactions

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Titel: HMGB1 B-Box Domain Associates Promote Protein–Polyelectrolyte Interactions
Autoren: Marten Kagelmacher, Marina Pigaleva, Ricardo Zarate, Leïla Bechtella, Kevin Pagel, Beate Koksch, Jens Dernedde, Andreas Herrmann, Thomas Risse
Quelle: The Journal of Physical Chemistry B. 129:9293-9303
Verlagsinformationen: American Chemical Society (ACS), 2025.
Publikationsjahr: 2025
Schlagwörter: Heparin, Chemie und zugeordnete Wissenschaften, FOS: Biological sciences, Genetics, Molecules
Beschreibung: HMGB1, a nuclear DNA-binding protein, can be secreted by activated immune cells or passively released from damaged cells. In such cases, HMGB1 functions as an alarmin that activates the immune system. Excessive inflammation may lead to pathogenesis, whereas this response can be dampened by polyanion binding, which impedes further receptor recognition. Moreover, HMGB1 is known to form liquid droplets in the cellular environment─a phase separation directly linked to its proper function. While the A-Box domain is believed to be primarily responsible for heparin binding due to its conserved binding site, the association and phase separation behavior of HMGB1 may be mediated by the B-box domain, owing to its extended hydrophobic regions. In this study, we first demonstrated that the B-box protein forms 30 nm large self-associates while maintaining its structure. Next, using molecularly sensitive EPR spectroscopy, we showed that the presence of these protein associates significantly enhances interactions with heparin. Notably, the local conformational changes induced by heparin are similar in both individual protein chains and their self-associated forms. To explain this effect, AlphaFold modeling was employed, revealing that the formation of protein multimers induces charge redistribution, resulting in an extended positively charged region that enhances electrostatic attraction to negatively charged polyanions such as heparin.
Publikationsart: Article
Other literature type
Sprache: English
ISSN: 1520-5207
1520-6106
DOI: 10.1021/acs.jpcb.5c02892
DOI: 10.17169/refubium-48936
Rights: CC BY
Dokumentencode: edsair.doi.dedup.....5e2c08aba34c914a28d2ea0cb83b0e35
Datenbank: OpenAIRE
Beschreibung
Abstract:HMGB1, a nuclear DNA-binding protein, can be secreted by activated immune cells or passively released from damaged cells. In such cases, HMGB1 functions as an alarmin that activates the immune system. Excessive inflammation may lead to pathogenesis, whereas this response can be dampened by polyanion binding, which impedes further receptor recognition. Moreover, HMGB1 is known to form liquid droplets in the cellular environment─a phase separation directly linked to its proper function. While the A-Box domain is believed to be primarily responsible for heparin binding due to its conserved binding site, the association and phase separation behavior of HMGB1 may be mediated by the B-box domain, owing to its extended hydrophobic regions. In this study, we first demonstrated that the B-box protein forms 30 nm large self-associates while maintaining its structure. Next, using molecularly sensitive EPR spectroscopy, we showed that the presence of these protein associates significantly enhances interactions with heparin. Notably, the local conformational changes induced by heparin are similar in both individual protein chains and their self-associated forms. To explain this effect, AlphaFold modeling was employed, revealing that the formation of protein multimers induces charge redistribution, resulting in an extended positively charged region that enhances electrostatic attraction to negatively charged polyanions such as heparin.
ISSN:15205207
15206106
DOI:10.1021/acs.jpcb.5c02892