Genetic control of the l-α-glycerophosphate system in Escherichia coli

Cozzarelli, Nicholas R.; Freedberg, W. B.; Lin, E. C. C.

doi:10.1016/0022-2836(68)90415-4

Cited by 143 publications

(74 citation statements)

References 43 publications

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“…Aerobic glycerol-3-phosphate dehydrogenase activity could not be detected in membranes of cells grown in the presence of glucose (data not presented). This result supports the notion that glucose-grown E. coli was non-induced for Glp function, since it has been suggested (Sanno et al, 1968) that the system for glycerol-facilitated diffusion in E. coli belongs to the L-aglycerophosphate regulon described by Cozzarelli, Freedberg & Lin (1968), to which the aerobic glycerol-3-phosphate dehydrogenase also belongs. Similar trends in variation of 1 /7 with concentration of glycerol were observed with induced cells although the values obtained were much higher.…”

Section: Re! S U L Tssupporting

confidence: 88%

Stopped-Flow Spectrophotometric Assay of Glycerol Permeation in Escherichia coli: Applicability and Limitations

Eze

McElhaney

1978

Journal of General Microbiology

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The passive permeation and facilitated diffusion of glycerol in various strains of Escherichia coli have been studied by stopped-flow spectrophotometry. Contrary to the prediction for glycerol entry by simple diffusion, the reciprocal relaxation time ( 1 /~, s-l) for the passive permeation of glycerol in cells grown in the presence of glucose was not constant but decreased as the glycerol concentration increased above 100 mM. This anomaly was not due to refractive index differences or to the presence of residual levels of the glycerol facilitator protein in non-induced cells. Although reciprocal relaxation times for glycerolinduced E. coli exhibited the expected elevation relative to non-induced cells, a similar anomalous decrease of 1 / T (s -l) with increasing glycerol concentration was observed. In addition, at early times after suspension in dilute buffer, the 1/7 (s-l) values obtained for induced or non-induced E. coli swelling in glycerol were considerably greater than for organisms incubated in dilute buffer for longer times. We concluded that either this spectrophotometric technique was not monitoring solely the permeation of glycerol into E. coli, or concentrations of glycerol above 100 mM significantly perturbed the strbcture of the E. coli cell envelope.

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Section: Re! S U L Tssupporting

confidence: 88%

Stopped-Flow Spectrophotometric Assay of Glycerol Permeation in Escherichia coli: Applicability and Limitations

Eze

McElhaney

1978

Journal of General Microbiology

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“…In Escherichia coli, the catabolism of glycerol and sn-glycerol-3-phosphate (G3P) is mediated by the components of the glp regulon (5). The genes of this regulon are organized in at least five operons which map in three separate regions on the chromosome (13).…”

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confidence: 99%

Regulation of glycerol metabolism in Pseudomonas aeruginosa: characterization of the glpR repressor gene

Schweizer

1996

J Bacteriol

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The operons of the glp regulon encoding the glycerol metabolic enzymes of Pseudomonas aeruginosa were hitherto believed to be positively regulated by the product of the glpR regulatory gene. During nucleotide sequence analysis of the region located upstream of the previously characterized glpD gene, encoding snglycerol-3-phosphate dehydrogenase, an open reading frame (glpR) was identified which encodes a protein of 251 amino acids that is 59% identical to the Glp repressor from Escherichia coli and could be expressed as a 28-kDa protein in a T7 expression system. Inactivation of chromosomal glpR by gene replacement resulted in constitutive expression of glycerol transport activity and glpD activity. These activities were strongly repressed after introduction of a multicopy plasmid containing the glpR gene; the same plasmid also efficiently repressed expression of a glpT-lacZ ؉ transcriptional fusion in an E. coli glpR mutant. Analysis of the glpD and glpF upstream region identified conserved palindromic sequences which were 70% identical to the E. coli glp operator consensus sequence. The results suggest that the operons of the glp regulon in P. aeruginosa are negatively regulated by the action of a glp repressor.In Escherichia coli, the catabolism of glycerol and sn-glycerol-3-phosphate (G3P) is mediated by the components of the glp regulon (5). The genes of this regulon are organized in at least five operons which map in three separate regions on the chromosome (13). The glpFK operon encodes a membrane diffusion facilitator for glycerol and a cytoplasmic glycerol kinase (37), the glpTQ operon encodes a membrane-associated G3P permease and a periplasmic glycerophosphodiester phosphodiesterase (8, 34), the glpACB operon (4) encodes anaerobic G3P dehydrogenase, the glpD gene encodes aerobic G3P dehydrogenase (1), and glpEG encodes proteins with unknown functions (22). By genetic (5) and physical means (21,22,37), it has conclusively been demonstrated that each operon is negatively regulated by a single repressor encoded by glpR, which maps adjacent to and is divergently transcribed from glpD (21, 22). The inducer for the E. coli glp regulon is G3P (5).The glp operons exhibit differential sensitivity to the glp repressor (13, 37). They are also subject to regulation by the cyclic-AMP-catabolite gene activator protein system (13, 37), and expression of the dehydrogenase genes (glpACB and glpD) is controlled by anaerobiosis (11).In Pseudomonas aeruginosa, the nature of glycerol metabolism has yet to be fully elucidated. Although biochemical and genetic data had originally demonstrated the presence of a high-affinity, energy-dependent transport system (30) associated with a periplasmic binding protein (35), subsequent experiments suggested that glycerol is transported by a high-affinity, binding protein-independent facilitated-diffusion system (41). This finding was corroborated by the recent cloning and sequencing of the glpFK operon, whose gene products exhibited ϳ80% identity to the E. coli glycerol diffusion faci...

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“…The synthesis of the GlpT system is induced by the presence of G3P in the growth medium (10). GlpT is a low-affinity antiporter that mediates the uptake of G3P by exchange against cellular Pi (1,16).…”

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confidence: 99%

Functional exchangeability of the ABC proteins of the periplasmic binding protein-dependent transport systems Ugp and Mal of Escherichia coli

Hekstra

Tommassen

1993

J Bacteriol

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The periplasmic binding protein-dependent transport systems Ugp and Mal of Escherichia coli transport sn-glycerol-3-phosphate and maltose, respectively. The UgpC and MalK proteins of these transport systems, which couple energy to the transport process by ATP-hydrolysis, are highly homologous, suggesting that they might be functionally exchangeable. Complementation experiments showed that UgpC expression could restore growth of a malK mutant on maltose as a carbon source, provided that it was expressed at a sufficiently high level in the absence of the integral inner membrane components UgpA and/or UgpE of the Ugp system. Conversely, MalK expression could complement ugpC mutants and restore the utilization of sn-glycerol-3-phosphate as a phosphate source. The hybrid transporters appeared to be less efficient than the wild-type systems. The complementation of ugpC mutations by MalK was strongly inhibited by the presence of glucose or a-methylglucoside, which are substrates of the phosphotransferase system. This inhibition is probably due to hypersensitivity of the hybrid UgpBAE-MalK transporter to inducer exclusion. UgpC expression did not complement the regulatory function of MalK in mal gene expression. The exchangeability of UgpC and MalK indicates that these proteins do not contribute to a substrate-binding site conferring substrate specificity to the transporter. These are the first examples of functional, hybrid periplasmic permeases in which the energy-coupling components could be functionally exchanged.

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Genetic control of the l-α-glycerophosphate system in Escherichia coli

Cited by 143 publications

References 43 publications

Stopped-Flow Spectrophotometric Assay of Glycerol Permeation in Escherichia coli: Applicability and Limitations

Stopped-Flow Spectrophotometric Assay of Glycerol Permeation in Escherichia coli: Applicability and Limitations

Regulation of glycerol metabolism in Pseudomonas aeruginosa: characterization of the glpR repressor gene

Functional exchangeability of the ABC proteins of the periplasmic binding protein-dependent transport systems Ugp and Mal of Escherichia coli

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