TY - JOUR
T1 - Genetic analysis of potassium transport loci in Escherichia coli
T2 - Evidence for three constitutive systems mediating uptake of potassium
AU - Dosch, D. C.
AU - Helmer, G. L.
AU - Sutton, S. H.
AU - Salvacion, F. F.
AU - Epstein, W.
PY - 1991
Y1 - 1991
N2 - The analysis of mutants of Escherichia coli that require elevated concentrations of K+ for growth has revealed two new genes, trkG, near minute 30 within the cryptic rac prophage, and trkH, near minute 87, the products of which affect constitutive K+ transport. The analysis of these and other trk mutations suggests that high rates of transport, previously considered to represent the activity of a single system, named TrkA, appear to be the sum of two systems, here named TrkG and TrkH. Each of these two is absolutely dependent on the product of the trkA gene, a cytoplasmic protein associated with the inner membrane (D. Bossemeyer, A. Borchard, D.C. Dosch, G.C. Helmer, W. Epstein, I.R. Booth, and E.P. Bakker, J. Biol. Chem. 264: 16403-16410, 1989). The TrkH system is also dependent on the products of the trkH and trkE genes, while the TrkG system is also dependent on the product of the trkG gene and partially dependent on the product of the trkE gene. It is suggested that the trkH and trkG products are membrane proteins that form the transmembrane path for the K+ movement of the respective systems. Two mutations altering the trkA product reduce the affinity for K+ of both TrkG and TrkH, indicating that changes in this peripheral protein can alter the conformation of the sites at which K+ is bound prior to transport. The TrkD system has a relatively modest rate of transport, is dependent solely on the product of the trkD gene, and is the sole saturable system for Cs+ uptake in this species (D. Bossemeyer, A. Schlosser, and E. P. Bakker, J. Bacteriol. 171:2219-2221, 1989).
AB - The analysis of mutants of Escherichia coli that require elevated concentrations of K+ for growth has revealed two new genes, trkG, near minute 30 within the cryptic rac prophage, and trkH, near minute 87, the products of which affect constitutive K+ transport. The analysis of these and other trk mutations suggests that high rates of transport, previously considered to represent the activity of a single system, named TrkA, appear to be the sum of two systems, here named TrkG and TrkH. Each of these two is absolutely dependent on the product of the trkA gene, a cytoplasmic protein associated with the inner membrane (D. Bossemeyer, A. Borchard, D.C. Dosch, G.C. Helmer, W. Epstein, I.R. Booth, and E.P. Bakker, J. Biol. Chem. 264: 16403-16410, 1989). The TrkH system is also dependent on the products of the trkH and trkE genes, while the TrkG system is also dependent on the product of the trkG gene and partially dependent on the product of the trkE gene. It is suggested that the trkH and trkG products are membrane proteins that form the transmembrane path for the K+ movement of the respective systems. Two mutations altering the trkA product reduce the affinity for K+ of both TrkG and TrkH, indicating that changes in this peripheral protein can alter the conformation of the sites at which K+ is bound prior to transport. The TrkD system has a relatively modest rate of transport, is dependent solely on the product of the trkD gene, and is the sole saturable system for Cs+ uptake in this species (D. Bossemeyer, A. Schlosser, and E. P. Bakker, J. Bacteriol. 171:2219-2221, 1989).
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U2 - 10.1128/jb.173.2.687-696.1991
DO - 10.1128/jb.173.2.687-696.1991
M3 - Article
C2 - 1987159
AN - SCOPUS:0026098110
SN - 0021-9193
VL - 173
SP - 687
EP - 696
JO - Journal of bacteriology
JF - Journal of bacteriology
IS - 2
ER -