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Uptake of N ‐acetyl‐ D ‐mannosamine: an essential intermediate in polysialic acid biosynthesis by Escherichia coli K92
Author(s) -
Revilla-Nuin Beatriz,
Reglero Angel,
Ferrero Miguel A,
Rodrı́guez-Aparicio Leandro B
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00413-5
Subject(s) - pep group translocation , chemistry , biochemistry , n acetylglucosamine , mannose , permease , glucosamine , escherichia coli , enzyme , gene
The N ‐acetyl‐ D ‐mannosamine (ManNAc) transport system of Escherichia coli K92 was studied when this bacterium was grown in a chemically defined medium containing ManNAc as carbon source. Kinetic measurements were carried out in vivo at 37°C in 25 mM phosphate buffer, pH 7.5. Under these conditions, the uptake rate was linear for at least 15 min and the calculated K m for ManNAc was 280 μM. The transport system was strongly inhibited by sodium arsenate (97%), potassium cyanide (84%) and 2,4‐dinitrophenol (88%) added at final concentrations of 1 mM (each). Analysis of bacterial ManNAc phosphotransferase activity revealed in vitro ManNAc phosphorylation activity only when phosphoenolpyruvate was present. These results strongly support the notion that ManNAc uptake depends on a specific phosphotransferase system. Study of specificities showed that N ‐acetylglucosamine and mannosamine specifically inhibited the transport of ManNAc in this bacterium. Analysis of expression revealed that the ManNAc transport system was induced by ManNAc, glucosamine, galactosamine, mannosamine and mannose but not by N ‐acetylglucosamine or N ‐acetylgalactosamine. Moreover, ManNAc permease was subject to glucose repression and cAMP stimulation. Full induction of the ManNAc transport system required the simultaneous presence of both cAMP and ManNAc.