Manganese Active Transport in
            <i>Escherichia coli</i>

Silver, Simón; Johnseine, Paula; King, Karen

doi:10.1128/jb.104.3.1299-1306.1970

Cited by 65 publications

(47 citation statements)

References 27 publications

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“…Interestingly, a related Mn(II) transport system was described in B. subtilis (Bhattacharyya, 1975) and was shown to constitute the primary uptake pathway of Cd(II) ions (for recent reviews, see Silver and Walderhaug, 1992). Some evidence suggests that MntH is in fact the Mn(II) transporter previously described in E. coli (Bhattacharyya, 1970;Silver et al 1970). First, E. coli MntH mediates high-capacity manganese ion uptake (Fig.…”

Section: Discussionmentioning

confidence: 88%

“…We have studied the effect of a yfeP null mutation and of overexpression of the corresponding protein on bacterial divalent cation transport. The functional characteristics presented here suggest that it encodes the previously described proton-dependent manganese transport system of E. coli (Bhattacharyya, 1970;Silver et al, 1970), here designated MntH.…”

Section: Introductionmentioning

confidence: 77%

“…In contrast, the observed preference of MntH for Mn(II) suggests that Mn(II) transport is the physiological function of the Nramp homologue in bacteria. A single active transport system selective for Mn(II) has been characterized so far in E. coli (Bhattacharyya, 1970;Silver et al 1970). To our knowledge, the presumed single gene encoding this proton-dependent transporter has not been identified (Silver, 1996).…”

Section: Discussionmentioning

confidence: 99%

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Identification of the Escherichia coli K‐12 Nramp orthologue (MntH) as a selective divalent metal ion transporter

Makui

Roig

Cole

et al. 2000

Molecular Microbiology

223

216

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SummaryThe Escherichia coli mntH (formerly yfeP) gene encodes a putative membrane protein (MntH) highly similar to members of the eukaryotic Nramp family of divalent metal ion transporters. To determine the function of E. coli MntH, a null mutant was created and MntH was overexpressed both in wild-type E. coli and in the metal-dependent mutant hflB1(Ts). At the restrictive temperature 428C, the mntH null mutation reduces the suppression of hflB1(Ts) thermosensitivity by exogenous divalent metals. Conversely, overexpression of MntH restores growth at 428C, increases suppression of the ts phenotype by Fe(II) and Ni(II) and renders hflB1(Ts) cells hypersensitive to Mn(II). Transport studies in intact cells show that MntH selectively facilitates uptake of 54 Mn(II) and 55 Fe(II) in a temperature-, time-and proton-dependent manner. Competition studies in uptake assays and growth inhibition experiments in hflB1(Ts) mutants together indicate that MntH is a divalent metal cation transporter of broad substrate specificity. The functional characteristics of MntH suggest that it corresponds to the previously described manganese transporter of E. coli. This study indicates that proton-dependent divalent metal ion uptake has been preserved in the Nramp family from bacteria to humans.

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Section: Discussionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 77%

Section: Discussionmentioning

confidence: 99%

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Identification of the Escherichia coli K‐12 Nramp orthologue (MntH) as a selective divalent metal ion transporter

Makui

Roig

Cole

et al. 2000

Molecular Microbiology

223

216

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“…Manganese(II) uptake and efflux and iron(II) uptake were determined by incubating cells in DT medium (0.4% tryptone peptone, 0.25% NaCl) with 54 Mn 21 (Amersham) as used by Silver et al (1970), with triplicate samples at each time point or concentration. Cells were then processed essentially as for Mg 21 transport assays from this laboratory (Grubbs et al, 1989).…”

Section: Transportmentioning

confidence: 99%

The NRAMP proteins of Salmonella typhimurium and Escherichia coli are selective manganese transporters involved in the response to reactive oxygen

Kehres

Zaharik

Finlay

et al. 2000

Molecular Microbiology

269

330

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NRAMPs (natural resistance‐associated macrophage proteins) have been characterized in mammals as divalent transition metal transporters involved in iron metabolism and host resistance to certain pathogens. The mechanism of pathogen resistance is proposed to involve sequestration of Fe2+ and Mn2+, cofactors of both prokaryotic and eukaryotic catalases and superoxide dismutases, not only to protect the macrophage against its own generation of reactive oxygen species, but to deny the cations to the pathogen for synthesis of its protective enzymes. NRAMP homologues are also present in bacteria. We report the cloning and characterization of the single NRAMP genes in Escherichia coli and Salmonella enterica ssp. typhimurium, and the cloning of two distinct NRAMP genes from Pseudomonas aeruginosa and an internal fragment of an NRAMP gene in Burkholderia cepacia. The genes are designated mntH because the two enterobacterial NRAMPs encode H+‐stimulated, highly selective manganese(II) transport systems, accounting for all Mn2+ uptake in each species under the conditions tested. For S. typhimurium MntH, the Km for 54Mn2+ (≈ 0.1 µM) was pH independent, but maximal uptake increased as pH decreased. Monovalent cations, osmotic strength, Mg2+ and Ca2+ did not inhibit 54Mn2+ uptake. Ni2+, Cu2+ and Zn2+ inhibited uptake with Kis greater than 100 µM, Co2+ with a Ki of 20 µM and Fe2+ with a Ki that decreased from 100 µM at pH 7.6 to 10 µM at pH 5.5. Fe3+ and Pb2+ inhibited weakly, exhibiting Kis of 50 µM, while Cd2+ was a potent inhibitor with a Ki of about 1 µM. E. coli MntH had a similar inhibition profile, except that Kis were three‐ to 10‐fold higher. Both S. typhimurium and E. coli MntH also transport 55Fe2+ however, the Kms are equivalent to the Kis for Fe2+ inhibition of Mn2+ uptake, and are thus too high to be physiologically relevant. In both S. typhimurium and E. coli, mntH::lacZ constructs were strongly induced by hydrogen peroxide, weakly induced by EDTA and unresponsive to paraquat, consistent with the presence of Fur and OxyR binding sites in the promoters. Strains overexpressing mntH were more susceptible to growth inhibition by Mn2+ and Cd2+ than wild type, and strains lacking a functional mntH gene were more susceptible to killing by hydrogen peroxide. In S. typhimurium strain SL1344, mntH mutants showed no defect in invasion of or survival in cultured HeLa or RAW264.7 macrophage cells; however, expression of mntH::lacZ was induced severalfold by 3 h after invasion of the macrophages. S. typhimurium mntH mutants showed only a slight attenuation of virulence in BALB/c mice. Thus, the NRAMP Mn2+ transporter MntH and Mn2+ play a role in bacterial response to reactive oxygen species and possibly have a role in pathogenesis.

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“…Mil2+ is a trace element generally required by 0,-evolving photosynthetic organisms ( MARTIN 1966, 1969). A few bacteria lacking 0, formation have also been found to show Mn2+ requirement for growth (SILVER and JASPER 1977). However, it has been difficult t o demonstrate a Mn2+ requirement for growth of Escherichiu coli (SILVER et a2.…”

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confidence: 99%

Mn²⁺ transport in the unicellular cyanobacterium Anacystis nidulans

Singh

1986

J. Basic Microbiol.

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MnZ+ uptake by wild type of Anacystis nidulam I U 625 follows MICHAELIS-MENTEN type kinetics with apparent saturation at 27 pmol/l of Mn". LINEWEAVER-BURK plot of the data reveals a Km of 25 pmol/l and I / , , , of 1.2 nmol/mg protein. min.The uptake values at different pH (pH 4.0 t o 9.0) exhibit a characteristic profile with an optimum at p H 6.0. The Mn2+ uptake rate in the dark is found to be similar to that in the light suggesting that energy for transport may not be directly derived from light reactions. The system seems t o be specific for Mn2+ transport since simultaneous addition of Mgz+ partially inhibited t h e uptake in a competitive manner. Further, the alterations in K m and TI , , , , , values of mutants with respect to that of wild type strains suggest a genetic control of the transport system.

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Manganese Active Transport in Escherichia coli

Cited by 65 publications

References 27 publications

Identification of the Escherichia coli K‐12 Nramp orthologue (MntH) as a selective divalent metal ion transporter

Identification of the Escherichia coli K‐12 Nramp orthologue (MntH) as a selective divalent metal ion transporter

The NRAMP proteins of Salmonella typhimurium and Escherichia coli are selective manganese transporters involved in the response to reactive oxygen

Mn²⁺ transport in the unicellular cyanobacterium Anacystis nidulans

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Manganese Active Transport in Escherichia coli

Cited by 65 publications

References 27 publications

Identification of the Escherichia coli K‐12 Nramp orthologue (MntH) as a selective divalent metal ion transporter

Identification of the Escherichia coli K‐12 Nramp orthologue (MntH) as a selective divalent metal ion transporter

The NRAMP proteins of Salmonella typhimurium and Escherichia coli are selective manganese transporters involved in the response to reactive oxygen

Mn2+ transport in the unicellular cyanobacterium Anacystis nidulans

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Mn²⁺ transport in the unicellular cyanobacterium Anacystis nidulans