Protein Domain : Magnesium/cobalt transport protein CorA IPR004488

Type	Family
Description	The CorA transport system is a primary Mg2+ transporter for Bacteria and Archaea. Some members in this family may have a function other than Mg2+ transport [ ]. Prokaryotic CorA can be classified into two sub-groups: (1) T. maritima type (group A) (2) E. coli and S.typhimurium type (group B) []. Thermotoga maritima CorA (TmCorA) has been reported to be an efflux system. It only has 2 transmembrane (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 [, ]. E. coli and S.typhimurium CorA was predicted to have an unusual membrane topology with a relatively large N-terminal periplasmic domain (CorA-PPD) followed by a compact C-terminal domain forming three transmembrane (TM1-3) segments [ , ]. However, a suggestion that TM1 is not completely transmembrane but rather peripheral to the membrane has been proposed, and in this scenario both terminalswould face the same side. A high-resolution structure from this group of proteins is needed to clarify this [ ].
Short Name	Mg/Co-transport_prot_CorA