Purification and Properties of a Leucine-binding Protein from Escherichia coli

Penrose, W.R.; Nichoalds, George E.; Piperno, Jeanette R.; Oxender, Dale L.

doi:10.1016/s0021-9258(18)94508-4

Cited by 145 publications

(13 citation statements)

References 18 publications

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“…A column for gene products has been added in Table 13 only to point out that some gene products are proteins and that genes have yet to be found for the leucine-isoleucine-valine-binding protein (14) and for the leucine-binding protein (4).…”

Section: Discussionmentioning

confidence: 99%

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Mutations Affecting the Different Transport Systems for Isoleucine, Leucine, and Valine in Escherichia coli K-12

et al. 1974

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Uptake of isoleucine, leucine, and valine in Escherichia coli K-12 is due to several transport processes for which kinetic evidence has been reported elsewhere. A very-high-affinity transport process, a high-affinity transport process, and three different low-affinity transport processes were described. In this paper the existence of these transport processes is confirmed by the isolation and preliminary characterization of mutants altered in one or more of them. The very-high-affinity transport process is missing either in strains carrying the brnR6 am mutation or in strains carrying the brn-8 mutation. This appears to be a pleiotropic effect since other transport systems are also missing. Mutant analysis shows that more than one transport system with high affinity is present. One of them, high-affinity 1, which needs the activity of a protein produced by the brnQ gene, transports isoleucine, leucine, and valine and is unaffected by threonine. The other, high-affinity 2, which needs the activity of a protein produced by the brnS gene, transports isoleucine, leucine, and valine; this uptake is inhibited by threonine which probably is a substrate. Another protein, produced by the brnR gene, is required for uptake through both high-affinity 1 and high-affinity 2 transport systems. The two systems therefore appear to work in parallel, brnR being a branching point. The brnQ gene is located close to phoA at 9.5 min on the chromosome of E. coli , the brnR gene is located close to lac at 9.0 min, and the brnS gene is close to pdxA at 1 min. A mutant lacking the low-affinity transport system for isoleucine was isolated from a strain in which the high-affinity system was missing because of a brnR mutation. This strain also required isoleucine for growth because of an ilvA mutation. The mutant lacking the low-affinity transport system was unable to grow on isoleucine but could grow on glycylisoleucine. This mutant had lost the low-affinity transport for isoleucine, whereas those for leucine and valine were unaffected. A pleiotropic consequence of this mutation ( brn-8 ) was a complete absence of the very-high-affinity transport system due either to the alteration of a common gene product or to any kind of secondary interference which inhibits it. Mutants altered in isoleucine-leucine-valine transport were isolated by taking advantage of the inhibition that valine exerts on the K-12 strain of E. coli . Mutants resistant both to valine inhibition (Val r ) and to glycylvaline inhibition are regulatory mutants. Val r mutants that are sensitive to glycylvaline inhibition are transport mutants. When the very-high-affinity transport process is repressed (for example by methionine) the frequency of transport mutants among Val r mutants is higher, and it is even higher if the high-affinity transport process is partially inhibited by leucine.

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Section: Discussionmentioning

confidence: 99%

“…We believe that probably many more genes will be found to be necessary for the function of the different transport systems. We have chosen to look for amber mutations in the "The leucine-isoleucine-valine (LIV)-binding protein described by Penrose et al (14).…”

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Mutations Affecting the Different Transport Systems for Isoleucine, Leucine, and Valine in Escherichia coli K-12

et al. 1974

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“…This binding activity appears to be associated with the LIVtransport system (13). Growth of E. coli in the presence of leucine causes a simultaneous decrease in the synthesis of the binding proteins and leucine transport activity (13). A second but minor transport system specific for leucine and a corresponding leucine specific-binding protein (L-binding protein) in E. coli have been identified by Furlong and Weiner (5).…”

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confidence: 98%

“…A binding protein (LIV-binding protein) has been isolated from the shock fluid. This binding activity appears to be associated with the LIVtransport system (13). Growth of E. coli in the presence of leucine causes a simultaneous decrease in the synthesis of the binding proteins and leucine transport activity (13).…”

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confidence: 99%

“…For isolation of the binding activities, the cells were grown to late exponential or early stationary growth phase. Cells were subjected to cold osmotic shock according to the procedure of Neu and Heppel (11), and the binding protein was purified as described previously (13). Binding activities were measured by the technique of equilibrium dialysis in a Hoefer equilibrium dialyzer.…”

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Multiplicity of Leucine Transport Systems in Escherichia coli K-12

1973

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The major component of leucine uptake in Escherichia coli K-12 is a common system for l -leucine, l -isoleucine, and l -valine (LIV-I) with a Michaelis constant ( K m ) value of 0.2 μM (LIV-I system). The LIV-binding protein appears to be associated with this system. It now appears that the LIV-I transport system and LIV-binding protein also serve for the entry of l -alanine, l -threonine, and possibly l -serine. A minor component of l -leucine entry occurs by a leucine-specific system (L-system) for which a specific leucine-binding protein has been isolated. A mutant has been obtained that shows increased levels of the LIV-I transport activity and increased levels of both of the binding proteins. Another mutant has been isolated that shows only a major increase in the levels of the leucine-specific transport system and the leucine-specific binding protein. A third binding protein that binds all three branched-chain amino acids but binds isoleucine preferentially has been identified. The relationship of the binding proteins to each other and to transport activity is discussed. A second general transport system (LIV-II system) with a K m value of 2 μM and a relatively low V max can be observed in E. coli . The LIV-II system is not sensitive to osmotic shock treatment nor to growth of cells in the presence of leucine. This high K m system, which is specific for the branched-chain amino acids, can be observed in membrane vesicle preparations.

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Active Transport of Amino Acids and Sugars

Curran¹

1972

Arch Intern Med

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This paper discusses active transport of amino acids and sugars and includes consideration of properties of the transport systems with respect to concentration dependence, specificity, and relationships to sodium concentration and cellular metabolism. The Na-dependence of these transport processes is particularly important, because an understanding of this characteristic should provide valuable information on the molecular mechanisms involved.The transport of sugars and amino acids across cell membranes obviously plays an important role in the life of the cell, since these pro¬ cesses are responsible in part for the substrates needed for cellular metab¬

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Purification and Properties of a Leucine-binding Protein from Escherichia coli

Cited by 145 publications

References 18 publications

Mutations Affecting the Different Transport Systems for Isoleucine, Leucine, and Valine in Escherichia coli K-12

Mutations Affecting the Different Transport Systems for Isoleucine, Leucine, and Valine in Escherichia coli K-12

Multiplicity of Leucine Transport Systems in Escherichia coli K-12

Active Transport of Amino Acids and Sugars

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