| Primary Identifier | IPR045863 | Type | Homologous_superfamily |
| Short Name | CorA_TM1_TM2 |
| description | This superfamily represents the transmembrane region (including TM1 and TM2) of the Mg2 transporter protein CorA. Thermotoga maritima CorA is an efflux system that forms funnel-shaped homopentamers, the tip of the funnel is formed from two C-terminal transmembrane (TM) helices from each monomer, and the large opening of the funnel from the N-terminal cytoplasmic domains []. This domain can also be found in zinc transport protein ZntB []and plant magnesium transporter MRS2 [].Thermotoga maritima CorA (TmCorA) has 2 TM domains,TM1 and TM2 [, , ]. The loop connecting TM1 and TM2 contains the conserved CorA signature motifs YGMNF and MPEL. With its N- and C-terminal ends face the cytosol and its similarity to the class II CorA (a CorA group lacking the MPEL motif and may transport divalent cations out of the cell), TmCorA is predicted to be primarily involved in ion efflux []. It forms a pentameric membrane protein channel featuring a possible ion discriminating aspartate ring at the cytoplasmic entrance of the pore and two distinct cytoplasmic metal binding sites per monomer, which could have regulatory roles [, ]. It has been suggested that eukaryotic CorA homologues have the same topology and overall structure as T. maritima CorA []. In budding yeasts, Mrs2 is an essential component of the major electrophoretic Mg2+ influx system in mitochondria []. Overexpression of Alr1 or Alr2 increases tolerance to Al3+ and Ga3+ ions []. Despite generally low sequence similarity, both human Mrs2 (also known as LPE10) and S. typhimurium CorA can restore Mg2+ uptake activity in Saccharomyces cerevisiae with inactive Mrs2 []. |
