4U9L

Structure of a membrane protein

Summary for 4U9L

• Entry DOI: 10.2210/pdb4u9l/pdb
• Related: 4U9N
• Descriptor: Magnesium transporter MgtE, MAGNESIUM ION, (2R)-2,3-dihydroxypropyl (9Z)-octadec-9-enoate, ... (4 entities in total)
• Functional Keywords: channel, magnesium, metal transport
• Biological source: Thermus thermophilus HB8
• Total number of polymer chains: 2
• Total formula weight: 40449.15

Authors

Takeda, H.,Hattori, M.,Nishizawa, T.,Yamashita, K.,Shah, S.T.A.,Caffrey, M.,Maturana, A.D.,Ishitani, R.,Nureki, O. (deposition date: 2014-08-06, release date: 2014-12-03, Last modification date: 2024-03-20)

Primary citation

Takeda, H.,Hattori, M.,Nishizawa, T.,Yamashita, K.,Shah, S.T.,Caffrey, M.,Maturana, A.D.,Ishitani, R.,Nureki, O.
Structural basis for ion selectivity revealed by high-resolution crystal structure of Mg(2+) channel MgtE
Nat Commun, 5:5374-5374, 2014

PubMed Abstract: Magnesium is the most abundant divalent cation in living cells and is crucial to several biological processes. MgtE is a Mg(2+) channel distributed in all domains of life that contributes to the maintenance of cellular Mg(2+) homeostasis. Here we report the high-resolution crystal structures of the transmembrane domain of MgtE, bound to Mg(2+), Mn(2+) and Ca(2+). The high-resolution Mg(2+)-bound crystal structure clearly visualized the hydrated Mg(2+) ion within its selectivity filter. Based on those structures and biochemical analyses, we propose a cation selectivity mechanism for MgtE in which the geometry of the hydration shell of the fully hydrated Mg(2+) ion is recognized by the side-chain carboxylate groups in the selectivity filter. This is in contrast to the K(+)-selective filter of KcsA, which recognizes a dehydrated K(+) ion. Our results further revealed a cation-binding site on the periplasmic side, which regulate channel opening and prevents conduction of near-cognate cations.

PubMed: 25367295
DOI: 10.1038/ncomms6374

Experimental method

X-RAY DIFFRACTION (2.3 Å)