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Pathway Description
Operon: Sugar Uptake
Escherichia coli
Category:
Metabolite Pathway
Sub-Category:
Signaling
Created: 2015-11-02
Last Updated: 2025-07-30
The ptsHI-crr operon in E. coli contains three genes which encode proteins that are part of the phosphoenolpyruvate-dependent sugar phosphotransferase system (PEP group translocation or sugar PTS). This is an active transport system used to bring sugars such as glucose and mannose into the cell. The operon can be activated by the cAMP-activated global transcriptional regulator CRP (CAP), which binds upstream of the promoter region and interacts with RNA polymerase, activating transcription of the operon. The operon can also be inhibited in several locations by various proteins. The catabolite repressor/activator protein Cra can bind to the promoter region, and depending on the binding of CRP, can either activate the operon's transcription if CRP is not bound, or can inhibit it if CRP is bound.
Protein mlc is a repressor that can bind to the promoter region of the operon, repressing transcription. It is involved in the repression and regulation of other proteins involved in the sugar PTS. Finally, the N-acetylglucosamine repressor can bind to the promoter region after being activated by the binding of N-acetyl-D-glucosamine 6-phosphate, allowing it to inhibit transcription of the operon.
The first gene in the operon, ptsH, encodes the phosphocarrier protein HPr, which is a general carrier protein in the sugar PTS that is not specific to the sugar being transported by the system. It takes a phosphoryl group from phosphoenolpyruvate (PEP) and transfers it to the EIIA domain of the carrier.
The second gene, ptsI, encodes phosphoenolpyruvate-protein phosphotransferase, another component of the sugar PTS that is not specific to the sugar. This enzyme is responsible for transferring the phosphoryl group from PEP to the protein HPr.
The final gene in the operon, crr, encodes theglucose-specific phosphotransferase enzyme IIA component, which combines with the PTS system N-acetylmuramic acid-specific EIIBC component to form the Enzyme E II protein. First, EIIA takes the phosphoryl group from HPr and transfers it to EIIB. Then EIIB transfers it across the cell membrane to EIIC via glucose, forming glucose-6-phosphate, which does not exit the cell naturally, allowing more glucose to be pumped into the cell forming a gradient.
References
Operon: Sugar Uptake References
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Ryu S, Garges S: Promoter switch in the Escherichia coli pts operon. J Biol Chem. 1994 Feb 18;269(7):4767-72.
Pubmed: 8106445
De Reuse H, Danchin A: The ptsH, ptsI, and crr genes of the Escherichia coli phosphoenolpyruvate-dependent phosphotransferase system: a complex operon with several modes of transcription. J Bacteriol. 1988 Sep;170(9):3827-37.
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Plumbridge J: DNA binding sites for the Mlc and NagC proteins: regulation of nagE, encoding the N-acetylglucosamine-specific transporter in Escherichia coli. Nucleic Acids Res. 2001 Jan 15;29(2):506-14.
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De Reuse H, Roy A, Danchin A: Analysis of the ptsH-ptsI-crr region in Escherichia coli K-12: nucleotide sequence of the ptsH gene. Gene. 1985;35(1-2):199-207. doi: 10.1016/0378-1119(85)90172-6.
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Saffen DW, Presper KA, Doering TL, Roseman S: Sugar transport by the bacterial phosphotransferase system. Molecular cloning and structural analysis of the Escherichia coli ptsH, ptsI, and crr genes. J Biol Chem. 1987 Nov 25;262(33):16241-53.
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Pubmed: 9278503
Hayashi K, Morooka N, Yamamoto Y, Fujita K, Isono K, Choi S, Ohtsubo E, Baba T, Wanner BL, Mori H, Horiuchi T: Highly accurate genome sequences of Escherichia coli K-12 strains MG1655 and W3110. Mol Syst Biol. 2006;2:2006.0007. doi: 10.1038/msb4100049. Epub 2006 Feb 21.
Pubmed: 16738553
Cossart P, Gicquel-Sanzey B: Cloning and sequence of the crp gene of Escherichia coli K 12. Nucleic Acids Res. 1982 Feb 25;10(4):1363-78. doi: 10.1093/nar/10.4.1363.
Pubmed: 6280141
Aiba H, Fujimoto S, Ozaki N: Molecular cloning and nucleotide sequencing of the gene for E. coli cAMP receptor protein. Nucleic Acids Res. 1982 Feb 25;10(4):1345-61. doi: 10.1093/nar/10.4.1345.
Pubmed: 6280140
Leclerc G, Noel G, Drapeau GR: Molecular cloning, nucleotide sequence, and expression of shl, a new gene in the 2-minute region of the genetic map of Escherichia coli. J Bacteriol. 1990 Aug;172(8):4696-700. doi: 10.1128/jb.172.8.4696-4700.1990.
Pubmed: 2198273
Jahreis K, Postma PW, Lengeler JW: Nucleotide sequence of the ilvH-fruR gene region of Escherichia coli K12 and Salmonella typhimurium LT2. Mol Gen Genet. 1991 Apr;226(1-2):332-6. doi: 10.1007/bf00273623.
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Yura T, Mori H, Nagai H, Nagata T, Ishihama A, Fujita N, Isono K, Mizobuchi K, Nakata A: Systematic sequencing of the Escherichia coli genome: analysis of the 0-2.4 min region. Nucleic Acids Res. 1992 Jul 11;20(13):3305-8. doi: 10.1093/nar/20.13.3305.
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Plumbridge JA: Sequence of the nagBACD operon in Escherichia coli K12 and pattern of transcription within the nag regulon. Mol Microbiol. 1989 Apr;3(4):505-15. doi: 10.1111/j.1365-2958.1989.tb00197.x.
Pubmed: 2668691
Peri KG, Goldie H, Waygood EB: Cloning and characterization of the N-acetylglucosamine operon of Escherichia coli. Biochem Cell Biol. 1990 Jan;68(1):123-37.
Pubmed: 2190615
Oshima T, Aiba H, Baba T, Fujita K, Hayashi K, Honjo A, Ikemoto K, Inada T, Itoh T, Kajihara M, Kanai K, Kashimoto K, Kimura S, Kitagawa M, Makino K, Masuda S, Miki T, Mizobuchi K, Mori H, Motomura K, Nakamura Y, Nashimoto H, Nishio Y, Saito N, Horiuchi T, et al.: A 718-kb DNA sequence of the Escherichia coli K-12 genome corresponding to the 12.7-28.0 min region on the linkage map. DNA Res. 1996 Jun 30;3(3):137-55. doi: 10.1093/dnares/3.3.137.
Pubmed: 8905232
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