The CorA Magnesium Transporter Gene Family

Kehres, David G.; Lawyer, Carl; Maguire, Michael E.

doi:10.1089/omi.1.1998.3.151

Cited by 104 publications

(88 citation statements)

References 31 publications

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“…ORF4 of pCIS3 encodes a protein with similarity to CorA proteins identified in many prokaryotes (Kehres et al, 1998), where they function as the dominant Mg# + -uptake system. ORF4 is similar in size to other corA genes and its deduced protein product contains three putative transmembrane domains (Fig.…”

Section: Absence Of Cora Results In Increased Cobalt Resistancementioning

confidence: 99%

“…The presence of multiple hsdS genes in a single host provides great potential for genetic recombination between them with the consequential possibility of increasing phage resistance. Furthermore, an ORF was identified on pCIS3, which shows homology to a ubiquitous class of magnesium transporters, known as corA (Kehres et al, 1998).…”

Section: Abbreviations : Abi Abortive Infection ; R/m Restriction/mmentioning

confidence: 99%

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Molecular characterization of the lactococcal plasmid pCIS3: natural stacking of specificity subunits of a type I restriction/modification system in a single lactococcal strain The GenBank accession numbers for the sequences reported in this paper are AF153410–AF153414.

2000

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A 6 1 kb plasmid from the Lactococcus lactis subsp. cremoris strain UC509.9, named pCIS3, was found to mediate a restriction/modification (R/M) phenotype. Nucleotide sequence analysis of pCIS3 revealed the presence of an hsdS gene, typical of type I R/M systems. The presence of this plasmid resulted in a 10 4 -fold reduction in the efficiency of plating (e.o.p.) of unmodified phage. In addition to the hsdS gene of pCIS3, two more hsdS genes were identified in strain UC509.9, one located on the chromosome downstream of a gene highly homologous to hsdM genes and a third on the smallest (4 kb) plasmid, named pCIS1. The replication region of pCIS3 was highly similar to that of a large family of lactococcal theta replicons. In addition, pCIS3 was found to encode a member of the CorA family of magnesium transporters.

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Section: Absence Of Cora Results In Increased Cobalt Resistancementioning

confidence: 99%

Section: Abbreviations : Abi Abortive Infection ; R/m Restriction/mmentioning

confidence: 99%

Molecular characterization of the lactococcal plasmid pCIS3: natural stacking of specificity subunits of a type I restriction/modification system in a single lactococcal strain The GenBank accession numbers for the sequences reported in this paper are AF153410–AF153414.

2000

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“…[22][23][24] The cation selectivity of CorA and ZntB was attributed to the difference in their signature motifs (CorA:YGMNFxxMPEL, ZntB: GxxG[I,V]NxGGxP). 12,25 The motif is located between two transmembrane ahelices on the outer surface of the membrane and it tends to be disordered in the crystal structures. [1][2][3] The mechanism of the ion selectivity for ZntB as a cation exporter has never been clear and it is not obvious why the metal ion needs to cross the entire pore to be selected for passage.…”

Section: Discussionmentioning

confidence: 99%

Structure and electrostatic property of cytoplasmic domain of ZntB transporter

et al. 2009

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ZntB is the distant homolog of CorA Mg 21 transporter within the metal ion transporter superfamily. It was early reported that the ZntB from Salmonella typhimurium facilitated efflux of Zn 21 and Cd 21 , but not Mg 21 . Here, we report the 1.90 Å crystal structure of the intracellular domain of ZntB from Vibrio parahemolyticus. The domain forms a funnel-shaped homopentamer that is similar to the full-length CorA from Thermatoga maritima, but differs from two previously reported dimeric structures of truncated CorA intracellular domains. However, no Zn 21 or Cd 21 binding sites were identified in the high-resolution structure. Instead, 25 well-defined Cl 2 ions were observed and some of these binding sites are highly conserved within the ZntB family. Continuum electrostatics calculations suggest that the central pore of the funnel is highly attractive for cations, especially divalents. The presence of the bound Cl 2 ions increases the stability of cations along the pore suggesting they could be important in enhancing cation transport.

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“…The cytoplasmic domain of CorA is a seven-stranded parallel/antiparallel -sheet ( 2 1 3 7 6 5 4 ) sandwiched between two sets of -helices ( 1,2,3) and ( 4,5,6) (Fig. 1).…”

mentioning

confidence: 99%

“…S1), is linked to the transmembrane helices by the long 7 helix (residues 251-312), termed the stalk helix. The stalk helix kinks as it enters the membrane, extends through the membrane, forms the first transmembrane helix (TM1; residues 293-312) and harbours the 'YGMNF' signature sequence of CorA (residues 311-315) 5,6 ( Fig. 2 and Supplementary Fig.…”

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confidence: 99%

Crystal structure of the CorA Mg2+ transporter

Лунин

Dobrovetsky²,

Khutoreskaya³

et al. 2006

Nature

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The magnesium ion, Mg 2+ , is essential for myriad biochemical processes and remains the only major biological ion whose transport mechanisms remain unknown. The CorA family of magnesium transporters is the primary Mg 2+ uptake system of most prokaryotes 1-3 and a functional homologue of the eukaryotic mitochondrial magnesium transporter 4 . Here we determine crystal structures of the full-length Thermotoga maritima CorA in an apparent closed state and its isolated cytoplasmic domain at 3.9 Å and 1.85Å resolution, respectively. The transporter is a funnel-shaped homopentamer with two transmembrane helices per monomer. The channel is formed by an inner group of five helices and putatively gated by bulky hydrophobic residues. The large cytoplasmic domain forms a funnel whose wide mouth points into the cell and whose walls are formed by five long helices that are extensions of the transmembrane helices. The cytoplasmic neck of the pore is surrounded, on the outside of the funnel, by a ring of highly conserved positively charged residues. Two negatively charged helices in the cytoplasmic domain extend back towards the membrane on the outside of the funnel and abut the ring of positive charge. An apparent Mg 2+ ion was bound between monomers at a conserved site in the cytoplasmic domain, suggesting a mechanism to link gating of the pore to the intra-cellular concentration of Mg 2+ . The CorA magnesium transporter is a homopentamer with fivefold symmetry about a central pore and can be divided into three parts (Fig. 1). A carboxy-terminal transmembrane domain comprises two transmembrane helices from each monomer (Fig. 2). The middle portion resembles a funnel, narrow at the entrance ( 5 Å) and wide at the mouth ( 20Å), that is formed largely by a long -helix extension of the inner transmembrane helix. Finally, a large cytoplasmic domain lies exterior to the funnel.The cytoplasmic domain of CorA is a seven-stranded parallel/antiparallel -sheet ( 2 1 3 7 6 5 4 ) sandwiched between two sets of -helices ( 1, 2, 3) and ( 4, 5, 6) ( Fig. 1). The domain fold is unlike all other known structures of ion channels or transporters and constitutes a new protein fold (see Supplementary Information). This domain, solved in its soluble form at 1.85 Å resolution ( Supplementary Fig. S1), is linked to the transmembrane helices by the long 7 helix (residues 251-312), termed the stalk helix. The stalk helix kinks as it enters the membrane, extends through the membrane, forms the first transmembrane helix (TM1; residues 293-312) and harbours the 'YGMNF' signature sequence of CorA (residues 311-315) 5,6 ( Fig. 2 and Supplementary Fig. S2). The five TM1 helices (residues 293-312) form the pore. After a short extracellular seven-amino-acid loop, the TM2 helix (residues 326-345) returns back to the cytoplasm and ends in a highly conserved C-terminal KKKKWL motif (Fig. 3). In the current structure, neither the extracellular loop nor the final two amino acids could be resolved.The cytoplasmic domain shows the lowest sequence conservati...

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The CorA Magnesium Transporter Gene Family

Cited by 104 publications

References 31 publications

Molecular characterization of the lactococcal plasmid pCIS3: natural stacking of specificity subunits of a type I restriction/modification system in a single lactococcal strain The GenBank accession numbers for the sequences reported in this paper are AF153410–AF153414.

Molecular characterization of the lactococcal plasmid pCIS3: natural stacking of specificity subunits of a type I restriction/modification system in a single lactococcal strain The GenBank accession numbers for the sequences reported in this paper are AF153410–AF153414.

Structure and electrostatic property of cytoplasmic domain of ZntB transporter

Crystal structure of the CorA Mg2+ transporter

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