3RKG: Structural And Functional Characterization Of The Yeast Mg2+ Channel Mrs2

Mg(2+) translocation across cellular membranes is crucial for a myriad of physiological processes. Eukaryotic Mrs2 transporters are distantly related to the major bacterial Mg(2+) transporter CorA, the structure of which displays a bundle of giant alpha-helices forming a long pore that extends beyond the membrane before widening into a funnel-shaped cytosolic domain. Here, a functional and structural analysis of the regulatory domain of the eukaryotic Mg(2+) channel Mrs2 from the yeast inner mitochondrial membrane is presented using crystallography, genetics, biochemistry and fluorescence spectroscopy. Surprisingly, the fold of the Mrs2 regulatory domain bears notable differences compared with the related bacterial channel CorA. Nevertheless, structural analysis showed that analogous residues form functionally critical sites, notably the hydrophobic gate and the Mg(2+)-sensing site. Validation of candidate residues was performed by functional studies of mutants in isolated yeast mitochondria. Measurements of the Mg(2+) influx into mitochondria confirmed the involvement of Met309 as the major gating residue in Mrs2, corresponding to Met291 in CorA.
PDB ID: 3RKGDownload
MMDB ID: 98794
PDB Deposition Date: 2011/4/18
Updated in MMDB: 2013/09
Experimental Method:
x-ray diffraction
Resolution: 1.28  Å
Source Organism:
Similar Structures:
Biological Unit for 3RKG: monomeric; determined by author and by software (PISA)
Molecular Components in 3RKG
Label Count Molecule
Protein (1 molecule)
Magnesium Transporter Mrs2, Mitochondrial(Gene symbol: MRS2)
Molecule annotation
Chemicals (5 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB