Magnesium transport in Salmonella typhimurium: sup 28 Mg sup 2+ transport by the CorA, MgtA, and MgtB systems

Journal Article · Fri Sep 01 00:00:00 EDT 1989 · Journal of Bacteriology; (USA)

OSTI ID:5404172

Snavely, M D; Florer, J B; Miller, C G; Maguire, M E ^[1]

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1. Case Western Reserve Univ., Cleveland, OH (USA)

Three loci in Salmonella typhimurium (corA, mgtA, and mgtB) code for components of distinct Mg{sup 2+} transport systems. Strains carrying one wild-type and two mutant alleles of the three loci were constructed to study the kinetics and specificity of ion transport of each system in isolation. The transport systems had different Km and Vmax values for Mg{sup 2+} uptake, and each was inhibited by other divalent cations in a distinct rank order of potency: for CorA, Mg{sup 2+} greater than Mn{sup 2+} greater than Co{sup 2+} greater than Ni{sup 2+} greater than Ca{sup 2+}; for MgtA, Zn{sup 2+} greater than or equal to Mg{sup 2+} greater than Ni{sup 2+} approximately Co{sup 2+} greater than Ca{sup 2+}; and for MgtB, Mg{sup 2+} approximately Ni{sup 2+} approximately Ni{sup 2+} greater than Mn2+ much greater than Ca{sup 2+}. Other differences among the three systems were apparent. The CorA transport system functioned as a Mg{sup 2+}-Mg{sup 2+} exchange system, mediating both efflux and influx of Mg{sup 2+}. Neither the MgtA nor the MgtB system could mediate Mg{sup 2+} efflux. Transport via the MgtB system was very temperature sensitive; Mg{sup 2+} was transported at 37 degrees C but not at 20{degrees}C. The MgtA and the MgtB transport systems were found to be regulated by the extracellular concentration of Mg{sup 2+}.

• OSTI ID: 5404172
• Journal Information: Journal of Bacteriology; (USA), Journal Name: Journal of Bacteriology; (USA) Vol. 171:9; ISSN JOBAA; ISSN 0021-9193
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
BACTERIA
BETA DECAY RADIOISOTOPES
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