TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
*1.A.35.1.1









Divalent cation (Mg2+, Co2+ and Ni2+) transport system, CorA.  Helical tilting and rotation in TM1 generates an iris-like motion that increases the diameter of the permeation pathway, triggering ion conduction, thus defining the gating mechanism (Dalmas et al. 2014).

Bacteria
Proteobacteria
CorA of E. coli (P0ABI4)
*1.A.35.1.2









Divalent cation (Mg2+, Co2+ and Ni2+) transport system, CorA

Bacteria
Proteobacteria
CorA of Salmonella typhimurium (P0A2R8)
*1.A.35.1.3









Magnesium transport protein CorA

Bacteria
Firmicutes
CorA of Bacillus subtilis
*1.A.35.2.1









Aluminum resistance protein AlR1p; LLR1; MNR1 (Mg2+ homeostasis transporter [Mg2+ regulated]) AlR1p and AlR2p (P43553; a close paralogue) both catalyze uptake of Mg2+ and a variety of heavy metals (da Costa et al., 2007).

Eukaryota
Fungi
AlR1p of Saccharomyces cerevisiae
*1.A.35.2.2









Putative manganese resistance, Mg2+ transport protein MnR2p
Eukaryota
Fungi
MnR2p of Saccharomyces cerevisiae
*1.A.35.2.3









Putative metal ion transporter C27B12.12c

Eukaryota
Fungi
C27B12.12c of Schizosaccharomyces pombe
*1.A.35.3.1









Divalent metal ion (Mg2+, Ca2+, Ni2+, etc.) transporter of 317 aas and 3 TMSs.  The cryo-EM structure shows a pentameric channel with an asymmetric domain structure and featuring differential separations between the trans-segments, probably reflecting mechanical coupling of the cytoplasmic domain to the transmembrane domain and suggesting a gating mechanism (Cleverley et al. 2015).

Archaea
Euryarchaeota
CorA of Methanocaldococcus jannaschii (Methanococcus jannaschii)
*1.A.35.3.2









Cobalt/magnesium transport protein, CorA.  The structure at 2.7 Å resolution is known. The CorA monomer has a C-terminal membrane domain containing two transmembrane segments and a large N-terminal cytoplasmic soluble domain. In the membrane, CorA forms a homopentamer shaped like a funnel which binds fully hydrated Mg2+ in the periplasm (Maguire 2006). A ring of positive charges are external to the ion-conduction pathway at the cytosolic membrane interface, and highly negatively charged helices in the cytosolic domain  appear to interact with the ring of positive charge to facilitate Mg2+ entry. Mg2+ ions are present in the cytosolic domain that are well placed to control the interaction of the ring of positive charge and the negatively charged helices, and thus, control Mg2+ entry (Maguire 2006).  Gating is achieved by helical rotation upon the binding of a metal ion substrate to the regulatory binding sites. The preference for Co2+ over Mg2+ is determined by the presence of threonine side chains in the channel (Nordin et al. 2013).

Bacteria
Thermotogae
CorA of Thermotoga maritima
*1.A.35.3.3









Putative metal ion transporter YfjQ
Bacteria
Firmicutes
YfjQ of Bacillus subtilis
*1.A.35.3.4









Putative CorA protein of 302 aas

Bacteria
Firmicutes
CorA of Streptococcus sanguinis
*1.A.35.3.5









MIP family protein of 366 aas. Mg2+,Co2+ and the CorA-specific inhibitor (Co(III) hexamine chloride) bind in the loop at the same binding site. This site includes the glutamic acid residue from the conserved "MPEL" motif (Hu et al. 2009).

Bacteria
Actinobacteria
CorA of Mycobacterium tuberculosis
*1.A.35.3.6









The CorA-homologous magnesium ion transporter of 831 aas, Mgt1.  Is critical for parasite development and virulence (Zhu et al. 2009).

Eukaryota
Kinetoplastida
Mgt1 of Leishmania major
*1.A.35.4.1









Zn2+/Cd2+ efflux system, ZntB. Mg2+ is not transported. Wan et al. 2011 reported crystal structures in dimeric and physiologically relevant homopentameric forms at 2.3 Å and 3.1 Å resolutions, respectively. The funnel-like structure is similar to that of the homologous Thermotoga maritima CorA Mg2+ channel and a Vibrio parahaemolyticus ZntB (VpZntB). However, the central α7 helix forming the inner wall of the StZntB funnel is oriented perpendicular to the membrane instead of the marked angle seen in CorA or VpZntB. Consequently, the StZntB funnel pore is cylindrical, not tapered, which may represent an "open" form of the ZntB soluble domain. There are three Zn2+ binding sites in the full-length ZntB, two of which could be involved in Zn2+ transport.

Bacteria
Proteobacteria
ZntB of Salmonella enterica serovar Typhimurium
*1.A.35.4.2









The ZntB Zn2+/Cd2+ transporter. The 1.9Å structure of the N-terminal cytoplasmic domain of ZntB has been solved (Tan et al., 2009).

Bacteria
Proteobacteria
ZntB of Vibrio parahaemolyticus (Q87M69)
*1.A.35.5.1









Mitochondrial inner membrane Mg2+ channel protein, Mrs2 (Schindl et al., 2007)
Eukaryota
Fungi
Mrs2 of Saccharomyces cerevisiae (Q01926)
*1.A.35.5.2









High affinity root Mg2+ transporter, Mrs2/MGT1.  Plants have up to 10 Mrs2 homologues, and they can form homo as well as heterooligomeric channels (Schmitz et al. 2013). Expression in an E. coli triple mutant, corA mgtA yhiD, which required high (>10 mM) Mg2+ for growth, allowed growth on >1 mM Mg2+ and resulted in Al3+ sensitivity (Ishijima et al. 2015).

Eukaryota
Viridiplantae
Mrs2 of Arabidposis thaliana (Q9SAH0)
*1.A.35.5.3









Magnesium transporter MRS2-11, chloroplastic (Magnesium Transporter 10) (AtMGT10).  Expression in an E. coli triple mutant, corA mgtA yhiD, which required high (>10 mM) Mg2+ for growth, allowed growth on >1 mM Mg2+ and resulted in Al3+ sensitivity (Ishijima et al. 2015).

Eukaryota
Viridiplantae
MGT10 of Arabidopsis thaliana
*1.A.35.5.4









Magnesium transporter MRS2-4 (Magnesium Transporter 6) (AtMGT6)
Eukaryota
Viridiplantae
MRS2-4 of Arabidopsis thaliana
*1.A.35.5.5









Mitochondrial inner membrane magnesium transporter MFM1; LPE10 (MRS2 function modulating factor 1)

Eukaryota
Fungi
MFM1 of Saccharomyces cerevisiae
*1.A.35.5.6









Magnesium transporter MRS2-5 (Magnesium Transporter 3) (AtMGT3)
Eukaryota
Viridiplantae
MRS2-5 of Arabidopsis thaliana