Functional roles of Mg2+ binding sites in ion-dependent gating of a Mg2+ channel, MgtE, revealed by solution NMR
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...
| Main Authors: | , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
eLife Sciences Publications Ltd
2018-04-01
|
| Series: | eLife |
| Subjects: | |
| Online Access: | https://elifesciences.org/articles/31596 |
| _version_ | 1797997480170749952 |
|---|---|
| author | Tatsuro Maruyama Shunsuke Imai Tsukasa Kusakizako Motoyuki Hattori Ryuichiro Ishitani Osamu Nureki Koichi Ito Andrès D Maturana Ichio Shimada Masanori Osawa |
| author_facet | Tatsuro Maruyama Shunsuke Imai Tsukasa Kusakizako Motoyuki Hattori Ryuichiro Ishitani Osamu Nureki Koichi Ito Andrès D Maturana Ichio Shimada Masanori Osawa |
| author_sort | Tatsuro Maruyama |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-04-11T10:33:40Z |
| format | Article |
| id | doaj.art-63addfb72b704ec8b3bc1d77ca4af0f6 |
| institution | Directory Open Access Journal |
| issn | 2050-084X |
| language | English |
| last_indexed | 2024-04-11T10:33:40Z |
| publishDate | 2018-04-01 |
| publisher | eLife Sciences Publications Ltd |
| record_format | Article |
| series | eLife |
| spelling | doaj.art-63addfb72b704ec8b3bc1d77ca4af0f62022-12-22T04:29:21ZengeLife Sciences Publications LtdeLife2050-084X2018-04-01710.7554/eLife.31596Functional roles of Mg2+ binding sites in ion-dependent gating of a Mg2+ channel, MgtE, revealed by solution NMRTatsuro Maruyama0Shunsuke Imai1Tsukasa Kusakizako2Motoyuki Hattori3https://orcid.org/0000-0002-5327-5337Ryuichiro Ishitani4https://orcid.org/0000-0002-4136-5685Osamu Nureki5https://orcid.org/0000-0003-1813-7008Koichi Ito6Andrès D Maturana7Ichio Shimada8Masanori Osawa9https://orcid.org/0000-0002-1285-4316Department of Physical Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, JapanDepartment of Physical Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, JapanDepartment of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, JapanState Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China; Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China; Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai, ChinaDepartment of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, JapanDepartment of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, JapanDepartment of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, JapanDepartment of Bioengineering Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, JapanDepartment of Physical Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, JapanDepartment of Physical Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan; Division of Physics for Life Functions, Faculty of Pharmacy, Keio University, Tokyo, JapanMagnesium 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.https://elifesciences.org/articles/31596Mg2+ homeostasisMg2+ channelMgtEgating mechanismNMRthermus thermophiles |
| spellingShingle | Tatsuro Maruyama Shunsuke Imai Tsukasa Kusakizako Motoyuki Hattori Ryuichiro Ishitani Osamu Nureki Koichi Ito Andrès D Maturana Ichio Shimada Masanori Osawa Functional roles of Mg2+ binding sites in ion-dependent gating of a Mg2+ channel, MgtE, revealed by solution NMR eLife Mg2+ homeostasis Mg2+ channel MgtE gating mechanism NMR thermus thermophiles |
| title | Functional roles of Mg2+ binding sites in ion-dependent gating of a Mg2+ channel, MgtE, revealed by solution NMR |
| title_full | Functional roles of Mg2+ binding sites in ion-dependent gating of a Mg2+ channel, MgtE, revealed by solution NMR |
| title_fullStr | Functional roles of Mg2+ binding sites in ion-dependent gating of a Mg2+ channel, MgtE, revealed by solution NMR |
| title_full_unstemmed | Functional roles of Mg2+ binding sites in ion-dependent gating of a Mg2+ channel, MgtE, revealed by solution NMR |
| title_short | Functional roles of Mg2+ binding sites in ion-dependent gating of a Mg2+ channel, MgtE, revealed by solution NMR |
| title_sort | functional roles of mg2 binding sites in ion dependent gating of a mg2 channel mgte revealed by solution nmr |
| topic | Mg2+ homeostasis Mg2+ channel MgtE gating mechanism NMR thermus thermophiles |
| url | https://elifesciences.org/articles/31596 |
| work_keys_str_mv | AT tatsuromaruyama functionalrolesofmg2bindingsitesiniondependentgatingofamg2channelmgterevealedbysolutionnmr AT shunsukeimai functionalrolesofmg2bindingsitesiniondependentgatingofamg2channelmgterevealedbysolutionnmr AT tsukasakusakizako functionalrolesofmg2bindingsitesiniondependentgatingofamg2channelmgterevealedbysolutionnmr AT motoyukihattori functionalrolesofmg2bindingsitesiniondependentgatingofamg2channelmgterevealedbysolutionnmr AT ryuichiroishitani functionalrolesofmg2bindingsitesiniondependentgatingofamg2channelmgterevealedbysolutionnmr AT osamunureki functionalrolesofmg2bindingsitesiniondependentgatingofamg2channelmgterevealedbysolutionnmr AT koichiito functionalrolesofmg2bindingsitesiniondependentgatingofamg2channelmgterevealedbysolutionnmr AT andresdmaturana functionalrolesofmg2bindingsitesiniondependentgatingofamg2channelmgterevealedbysolutionnmr AT ichioshimada functionalrolesofmg2bindingsitesiniondependentgatingofamg2channelmgterevealedbysolutionnmr AT masanoriosawa functionalrolesofmg2bindingsitesiniondependentgatingofamg2channelmgterevealedbysolutionnmr |