Mass spectrometric approach for characterizing the disordered tail regions of the histone H2A/H2B dimer

Kazumi Saikusa, Aritaka Nagadoi, Kana Hara, Sotaro Fuchigami, Hitoshi Kurumizaka, Yoshifumi Nishimura, Satoko Akashi

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    Abstract

    The histone H2A/H2B dimer is a component of nucleosome core particles (NCPs). The structure of the dimer at the atomic level has not yet been revealed. A possible reason for this is that the dimer has three intrinsically disordered tail regions: the N-and C-termini of H2A and the N-terminus of H2B. To investigate the role of the tail regions of the H2A/H2B dimer structure, we characterized behaviors of the H2A/H2B mutant dimers, in which these functionally important disordered regions were depleted, using mass spectrometry (MS). After verifying that the acetylation of Lys residues in the tail regions had little effect on the gas-phase conformations of the wild-type dimer, we prepared two histone H2A/H2B dimer mutants: an H2A/H2B dimer depleted of both N-termini (dN-H2A/dN-H2B) and a dimer with the N-and C-termini of H2A and the N-terminus of H2B depleted (dNC-H2A/dN-H2B). We analyzed these mutants using ion mobility-mass spectrometry (IM-MS) and hydrogen/deuterium exchange mass spectrometry (HDX-MS). With IM-MS, reduced structural diversity was observed for each of the tail-truncated H2A/H2B mutants. In addition, global HDX-MS proved that the dimer mutant dNC-H2A/dN-H2B was susceptible to deuteration, suggesting that its structure in solution was somewhat loosened. A partial relaxation of the mutant's structure was demonstrated also by IM-MS. In this study, we characterized the relationship between the tail lengths and the conformations of the H2A/H2B dimer in solution and gas phases, and demonstrated, using mass spectrometry, that disordered tail regions play an important role in stabilizing the conformation of the core region of the dimer in both phases.

    Original languageEnglish
    Pages (from-to)2220-2227
    Number of pages8
    JournalAnalytical Chemistry
    Volume87
    Issue number4
    DOIs
    Publication statusPublished - 2015 Feb 17

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    ASJC Scopus subject areas

    • Analytical Chemistry

    Cite this

    Saikusa, K., Nagadoi, A., Hara, K., Fuchigami, S., Kurumizaka, H., Nishimura, Y., & Akashi, S. (2015). Mass spectrometric approach for characterizing the disordered tail regions of the histone H2A/H2B dimer. Analytical Chemistry, 87(4), 2220-2227. https://doi.org/10.1021/ac503689w