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Novel Mg 2+ binding sites in the cytoplasmic domain of the MgtE Mg 2+ channels revealed by X-ray crystal structures
- Source :
- Acta Biochimica et Biophysica Sinica, Vol 55, Pp 683-690 (2023)
- Publication Year :
- 2023
- Publisher :
- China Science Publishing & Media Ltd., 2023.
-
Abstract
- MgtE is a Mg 2+-selective channel regulated by the intracellular Mg 2+ concentration. MgtE family proteins are highly conserved in all domains of life and contribute to cellular Mg 2+ homeostasis. In humans, mutations in the SLC41 proteins, the eukaryotic counterparts of the bacterial MgtE, are known to be associated with various diseases. The first MgtE structure from a thermophilic bacterium, Thermus thermophilus, revealed that MgtE forms a homodimer consisting of transmembrane and cytoplasmic domains with a plug helix connecting the two and that the cytoplasmic domain possesses multiple Mg 2+ binding sites. Structural and electrophysiological analyses revealed that the dissociation of Mg 2+ ions from the cytoplasmic domain induces structural changes in the cytoplasmic domain, leading to channel opening. Thus, previous works showed the importance of MgtE cytoplasmic Mg 2+ binding sites. Nevertheless, due to the limited structural information on MgtE from different species, the conservation and diversity of the cytoplasmic Mg 2+ binding site in MgtE family proteins remain unclear. Here, we report crystal structures of the Mg 2+-bound MgtE cytoplasmic domains from two different bacterial species, Chryseobacterium hispalense and Clostridiales bacterium, and identify multiple Mg 2+ binding sites, including ones that were not observed in the previous MgtE structure. These structures reveal the conservation and diversity of the cytoplasmic Mg 2+ binding site in the MgtE family proteins.
Details
- Language :
- English
- ISSN :
- 16729145
- Volume :
- 55
- Database :
- Directory of Open Access Journals
- Journal :
- Acta Biochimica et Biophysica Sinica
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.b33394673e7e4f3d9d79717a1de46f95
- Document Type :
- article
- Full Text :
- https://doi.org/10.3724/abbs.2023067