Glycerol Utilization by Facilitated Diffusion Coupled to Phosphorylation in Bacteria
Escherichia coli and probably most other bacteria entrap glycerol by the tandem action of a cytoplasmic membrane protein which catalyzes facilitated diffusion and an ATP-dependent kinase subject to feedback inhibition. The facilitator protein behaves as though it provides an aqueous channel with an effective pore diameter of about 0.4 nm. The kinase is also not highly specific, since, in addition to glycerol, the enzyme can phosphorylate dihydroxyacetone and Lglyceraldehye. Under physiological conditions, however, the two proteins appear to function as a complex, and together they impose a more stringent substrate specificity.
Whereas wild-type E. coli can grow at a maximal rate on glycerol at concentrations well below 0.05 mM, mutants lacking the facilitator require at least 5 mM of the compound to achieve full growth rate. Utilization of glycerol as sole carbon and energy source by wild-type cells is rate-limited by the action of fructose-1,6-bisphosphate as a noncompetitive inhibitor. Utilization of glycerol in the presence of glucose is prevented at least in part by increased concentration of dephosphorylated factor IIIGlc of the phosphoenolpyruvate phosphotransferase system. This effect seems to be exerted either on the kinase alone or on both the kinase and the facilitator.
Glycerol is bactericidal to mutants synthesizing high levels of a kinase which is insensitive to feedback control by fructose-1, 6-bisphosphate. The cells are killed by the copious production of methylglyoxal from the elevated pool of dihydroxyacetone phosphate. In contrast, glycerol is bacteriostatic to mutants blocked in the dehydrogenation of sn-glycerol 3-phosphate.
It is suggested that the evolution of a concentrative mechanism for the uptake of glycerol in bacterial and other kinds of cells is prevented by the high intrinsic permeability of biological membranes to the compound, a property which would make active transport a Sisyphean process.
KeywordsPermeability Fructose Turbidity Thiourea Hydrolase
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- Danielli, J.F., 1954, The present position in the field of facilitated diffusion and selective active transport, p. 1, in: “Recent Developments in Cell Physiology,” J.A. Kitching, ed., Academic Press, New York.Google Scholar
- de Riel, J.K., and Paulus, H., 1978c, Subunit dissociation in the allosteric regulation of glycerol kinase from Escherichia coli. 3. Role in desensitization, Biochemistry, 17: 5146.Google Scholar
- Edgar, W., Forrest, I.S., Holms, W.H., and Jasani, B., 1972, The control of glycerol utilization by glucose metabolism, Biochem. J., 127: 59.Google Scholar
- Fischer, A., 1903, “Vorlesungen über Bakterien,” Gustav Fischer, Jena.Google Scholar
- Hayashi, S., and Lin, E.C.C., 1965, Capture of glycerol by cells of Escherichia coli, Biochim. Biophys. Acta, 94: 479.Google Scholar
- Jacobs, M.H., 1954, A case of apparent physiological competition between ethylene glycol and glycerol, Biol. Bull., 107: 314.Google Scholar
- Jacobs, M.H., and Corson, S.A., 1934, The influence of minute traces of copper on certain hemolytic processes, Biol. Bull., 67: 325.Google Scholar
- Kalckar, H., 1937, Phosphorylation in kidney tissue, Enzymologia, 2: 47.Google Scholar
- Lueking, D., Pike, L., and Sojka, G., 1975, Glycerol utilization by a mutant of Rhodopseudomonas capsulata, J. Bacteriol., 125: 750.Google Scholar
- Luria, S.E., 1965, On the evolution of the lactose utilization gene system in enteric bacteria, p. 357, in: “Evolving Genes and Proteins,” H.J. Vogel, ed., Academic Press, New York.Google Scholar
- Mitchell, P., and Moyle, J., 1956, Osmotic function and structure in bacteria, p. 150, in: “Bacterial Anatomy,” Sixth Symp. Soc. Gen. Microbiol., Cambridge University Press, London.Google Scholar
- Perlman, R.L., and Pastan, I., 1969, Pleiotropic deficiency of carbohydrate utilization in an adenyl cyclase deficient mutant of Escherichia coli, Biochem. Biophys. Res. Commun., 37: 151.Google Scholar
- Postma, P.W., and Roseman, S., 1976, The bacterial phosphoenolpyruvate:sugar phosphotransferase system, Biochim. Biophys. Acta, 457: 213.Google Scholar
- Saier, M.H., Jr., Straud, H., Massman, L.S., Judice, J.J., Newman, M.J., and Feucht, B.U., 1978, Permease-specific mutations in Salmonella typhimurium and Escherichia coli that release the glycerol, maltose, melibiose, and lactose transport systems from regulation by the phosphoenolpyruvate:sugar phosphotransferase system in Salmonella typhimurium, J. Bacteriol., 133: 1358.PubMedGoogle Scholar
- Thorner, J.W., and Paulus, H., 1973b, Glycerol and glycerate kinases, p. 487, in: “The Enzymes,” vol. 8, P.D. Boyer, ed., Academic Press, New York.Google Scholar