Functional roles of Mg2+ binding sites in ion-dependent gating of a Mg2+ channel, MgtE, revealed by solution NMR

Tatsuro Maruyama, Shunsuke Imai, Tsukasa Kusakizako, Motoyuki Hattori, Ryuichiro Ishitani, Osamu Nureki, Koichi Ito, Andrès D. Maturana, Ichio Shimada, Masanori Osawa

研究成果: Article

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Magnesium ions (Mg2+) are divalent cations essential for various cellular functions. Mg2+ homeostasis is maintained through Mg2+ channels such as MgtE, a prokaryotic Mg2+ channel whose gating is regulated by intracellular Mg2+ levels. Our previous crystal structure of MgtE in the Mg2+-bound, closed state revealed the existence of seven crystallographically-independent Mg2+-binding sites, Mg1–Mg7. The role of Mg2+-binding to each site in channel closure remains unknown. Here, we investigated Mg2+-dependent changes in the structure and dynamics of MgtE using nuclear magnetic resonance spectroscopy. Mg2+-titration experiments, using wild-type and mutant forms of MgtE, revealed that the Mg2+ binding sites Mg1, Mg2, Mg3, and Mg6, exhibited cooperativity and a higher affinity for Mg2+, enabling the remaining Mg2+ binding sites, Mg4, Mg5, and Mg7, to play important roles in channel closure. This study revealed the role of each Mg2+-binding site in MgtE gating, underlying the mechanism of cellular Mg2+ homeostasis.

元の言語English
記事番号e31596
ジャーナルeLife
7
DOI
出版物ステータスPublished - 2018 4 3

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ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)

これを引用

Maruyama, T., Imai, S., Kusakizako, T., Hattori, M., Ishitani, R., Nureki, O., Ito, K., Maturana, A. D., Shimada, I., & Osawa, M. (2018). Functional roles of Mg2+ binding sites in ion-dependent gating of a Mg2+ channel, MgtE, revealed by solution NMR. eLife, 7, [e31596]. https://doi.org/10.7554/eLife.31596