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Escherichia coli K-12 substr. MG1655 Polypeptide: chitobiose PTS permease - ChbA subunit



Gene: chbA Accession Numbers: EG10142 (EcoCyc), b1736, ECK1734

Synonyms: chbC, celC, EIIAchb, Enzyme IIAchb, EIIIchb, Enzyme IIIchb

Regulation Summary Diagram: ?

Component of: chitobiose PTS permease (extended summary available)

Summary:
ChbA contains a PTS Enzyme IIA domain.

IIAchb has been shown to form stable homodimers [Keyhani00c], though the solution structure of a mutant IIAChb determined by NMR spectroscopy suggests that a homotrimer is the primary oligomeric state of IIAchb. The active site histidine (His89) is located within a crevice formed at the interface of two adjacent subunits of the EIIAChb trimer [Tang05a]. A solution structure of a ChbA-ChbB complex has been obtained and the interaction sites mapped. The protruding active site of ChbB containing the active site cysteine residue (Cys10) is buried within the cleft formed by the adjacent subunits of the ChbA trimer [Jung10a]. The solution structure of a ChbA-HPr complex shows the active site histidine (His15) of HPr buried within this same cleft [Jung12]. HPr and CbhB have no similarity in either overall structure or local structure at their active site; despite this they bind to highly overlapping binding sites on ChbA.

Stable complexes with a 1:1 ratio of IIAchb and IIBchb subunits have been identified which dissociate when IIBchb is phosphorylated [Keyhani00b, Keyhani00a].

chbA: N,N'-diacetylchitobiose A

Gene Citations: [Reizer90, Keyhani97]

Locations: cytosol

Map Position: [1,817,479 <- 1,817,829] (39.17 centisomes)
Length: 351 bp / 116 aa

Molecular Weight of Polypeptide: 12.748 kD (from nucleotide sequence)

Unification Links: ASAP:ABE-0005792 , CGSC:18484 , EchoBASE:EB0140 , EcoGene:EG10142 , EcoliWiki:b1736 , ModBase:P69791 , OU-Microarray:b1736 , PortEco:chbA , PR:PRO_000022272 , Protein Model Portal:P69791 , RefSeq:NP_416250 , RegulonDB:EG10142 , SMR:P69791 , String:511145.b1736 , UniProt:P69791

Relationship Links: InterPro:IN-FAMILY:IPR003188 , PDB:Structure:1WCR , PDB:Structure:2LRK , PDB:Structure:2LRL , PDB:Structure:2WWV , PDB:Structure:2WY2 , Pfam:IN-FAMILY:PF02255 , Prosite:IN-FAMILY:PS51095

Gene-Reaction Schematic: ?

Genetic Regulation Schematic: ?

GO Terms:

Biological Process: GO:0009401 - phosphoenolpyruvate-dependent sugar phosphotransferase system Inferred from experiment Inferred by computational analysis [UniProtGOA11, GOA01, Reizer90, Keyhani00d, Keyhani00b]
GO:0034219 - carbohydrate transmembrane transport Inferred from experiment Inferred by computational analysis [Reizer90, Keyhani00d]
GO:0051260 - protein homooligomerization Inferred from experiment [Tang05a, Keyhani00a]
GO:1902815 - N,N'-diacetylchitobiose import Inferred from experiment [Keyhani00d]
GO:0006810 - transport Inferred by computational analysis [UniProtGOA11]
GO:0008152 - metabolic process Inferred by computational analysis [UniProtGOA11]
GO:0008643 - carbohydrate transport Inferred by computational analysis [UniProtGOA11]
Molecular Function: GO:0005515 - protein binding Inferred from experiment [Strauss75]
GO:0090566 - protein-phosphocysteine-N,N'-diacetylchitobiose phosphotransferase system transporter activity Inferred from experiment Inferred by computational analysis [Reizer90, Keyhani00d]
GO:0016740 - transferase activity Inferred by computational analysis [UniProtGOA11]
Cellular Component: GO:0005829 - cytosol Inferred from experiment Inferred by computational analysis [DiazMejia09, Keyhani00a]
GO:0005737 - cytoplasm Inferred by computational analysis [UniProtGOA11a, UniProtGOA11]

MultiFun Terms: metabolism carbon utilization carbon compounds
transport Group Translocators Phosphotransferase Systems (PEP-dependent PTS)

Essentiality data for chbA knockouts: ?

Growth Medium Growth? T (°C) O2 pH Osm/L Growth Observations
LB Lennox Yes 37 Aerobic 7   Yes [Baba06, Comment 1]
M9 medium with 1% glycerol Yes 37 Aerobic 7.2 0.35 Yes [Joyce06, Comment 2]
MOPS medium with 0.4% glucose Yes 37 Aerobic 7.2 0.22 Yes [Baba06, Comment 1]

Subunit of: chitobiose PTS permease

Synonyms: EIIcel, EIIchb, Enzyme IIcel, Enzyme II chb

Subunit composition of chitobiose PTS permease = [ChbA][ChbC][ChbB]
         chitobiose PTS permease - ChbA subunit = ChbA (extended summary available)
         chitobiose PTS permease - ChbC subunit = ChbC (summary available)
         chitobiose PTS permease - ChbB subunit = ChbB (summary available)

Summary:
ChbBCA belongs to the functional superfamily of the PEP-dependent, sugar transporting phosphotransferase system (PTSsugar). The N,N'-diacetylchitobiose (chitobiose) PTS transporter takes up exogenous chitobiose, the β1-4 linked dimer of N-acetylglucosamine and major breakdown product of chitin, releasing the phosphate ester into the cell cytoplasm in preparation for hydrolysis and metabolism, primarily via glycolysis [Keyhani97]. Diacetylchitobiose, triacetylchitobiose and the non-metabolizable analogue methyl β-diacetylthiochitobiose are all inducers and substrates of the chitobiose permease [Keyhani00d].

The chitobiose PTS transporter requires the general PTS enzymes Enzyme I (PtsI) and HPr (PtsH) as well as Enzyme IIchb for transport and phosphorylation of its substrates [Keyhani00d]. The Enzyme IIchb complex, possesses three polypeptide chains: ChbA, ChbB, and ChbC [Parker90a, Reizer90]. It is homologous to the well-characterized lactose-specific PTS Enzyme II of Gram-positive bacteria [Reizer90]. ChbC is an integral membrane transport protein while IIA (ChbA) and IIB (ChbB) are soluble [Reizer90, Keyhani00a]. Enzyme IIchb mediates a phosphotransfer and transport reaction whereby a phosphoryl group is transferred from phospho-HPr to ChbA, from ChbA to ChbB and then onto the incoming sugar substrate [Keyhani00d, Keyhani00c, Keyhani00b]. ChbCBA is a member of the PTS Lactose - N,N'-diacetylchitobiose-β-glycoside (Lac) family of transporters [Saier14].

E. coli is chemotactic towards chitobiose [Keyhani97].

The chb operon contains in addition to chbBCA, the chbR gene, which encodes a negative regulatory protein, the chbF gene encoding an enzyme that functions as an acetylchitobiose-6-phosphate hydrolase and the chbG encoding a chitooligosaccharide deacetylase. The operon gene order is chbBCARFG. The chb operon is subject to complex regulation by three transcription factors: ChbR, NagC and cyclic AMP-cyclic AMP receptor protein complex [Plumbridge04].

Mutations can occur within the chb system which allow the uptake of the β-glucosides arbutin, salicin, and cellobiose. Such mutations include integration of insertion sequences upstream of the transcriptional start site and point mutations of the ChbR repressor that allow recognition of these β-glucosides as inducers [Kricker84, Hall86, Kricker87, Hall87, Hall87a, Parker90a]. Cellobiose positive strains contain mutations that alter the regulation of chb genes. Specifically the mutations result in loss of NagC repression and gain of function in ChbR. This suggests that the wild-type permease can recognize and transport cellobiose [Kachroo07]

chb: N,N'-diacetylchitobiose

Citations: [Parker90]

GO Terms:

Biological Process: GO:0009401 - phosphoenolpyruvate-dependent sugar phosphotransferase system Inferred from experiment Inferred by computational analysis [Reizer90, Keyhani00d, Keyhani00b]
GO:1902815 - N,N'-diacetylchitobiose import Inferred from experiment [Keyhani97, Keyhani00d]
Molecular Function: GO:0090566 - protein-phosphocysteine-N,N'-diacetylchitobiose phosphotransferase system transporter activity Inferred from experiment Inferred by computational analysis [Reizer90, Keyhani00b, Keyhani00d]

Credits:
Last-Curated ? 25-Mar-2014 by Mackie A , Macquarie University


Enzymatic reaction of: transport and phosphorylation of chitobiose (chitobiose PTS permease)

Summary:
The Km for uptake of the non-metabolizable analogue methyl β-diacetylthiochitobiose is 50-100µM [Keyhani00d]


Enzymatic reaction of: transport and phosphorylation of cellobiose (chitobiose PTS permease)

Note: The enzyme may catalyze this reaction in vitro, but this reaction is not considered to be physiologically relevant.

Citations: [Kachroo07]


Sequence Features

Feature Class Location Citations Comment
Extrinsic-Sequence-Variant 14
[UniProt10]
Alternate sequence: A → V; UniProt: (in strain: ECOR 1);
Conserved-Region 15 -> 113
[UniProt09]
UniProt: PTS EIIA type-3;
Sequence-Conflict 43 -> 44
[Parker90, UniProt10]
Alternate sequence: KQ → NR; UniProt: (in Ref. 1; CAA37071);
Extrinsic-Sequence-Variant 52
[UniProt10]
Alternate sequence: A → T; UniProt: (in strain: ECOR 61);
Extrinsic-Sequence-Variant 59
[UniProt10]
Alternate sequence: M → I; UniProt: (in strain: ECOR 50);
Active-Site 89
[UniProt10a]
UniProt: Tele-phosphohistidine intermediate; by HPr; Non-Experimental Qualifier: by similarity;


Gene Local Context (not to scale): ?

Transcription Unit:

Notes:

History:
10/20/97 Gene b1736 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG10142; confirmed by SwissProt match.


References

Baba06: Baba T, Ara T, Hasegawa M, Takai Y, Okumura Y, Baba M, Datsenko KA, Tomita M, Wanner BL, Mori H (2006). "Construction of Escherichia coli K-12 in-frame, single-gene knockout mutants: the Keio collection." Mol Syst Biol 2;2006.0008. PMID: 16738554

DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114

GOA01: GOA, DDB, FB, MGI, ZFIN (2001). "Gene Ontology annotation through association of InterPro records with GO terms."

Hall86: Hall BG, Betts PW, Kricker M (1986). "Maintenance of the cellobiose utilization genes of Escherichia coli in a cryptic state." Mol Biol Evol 3(5);389-402. PMID: 2832693

Hall87: Hall BG, Betts PW (1987). "Cryptic genes for cellobiose utilization in natural isolates of Escherichia coli." Genetics 115(3);431-9. PMID: 3552874

Hall87a: Hall BG, Faunce W (1987). "Functional genes for cellobiose utilization in natural isolates of Escherichia coli." J Bacteriol 169(6);2713-7. PMID: 3034866

Joyce06: Joyce AR, Reed JL, White A, Edwards R, Osterman A, Baba T, Mori H, Lesely SA, Palsson BO, Agarwalla S (2006). "Experimental and computational assessment of conditionally essential genes in Escherichia coli." J Bacteriol 188(23);8259-71. PMID: 17012394

Jung10a: Jung YS, Cai M, Clore GM (2010). "Solution structure of the IIAChitobiose-IIBChitobiose complex of the N,N'-diacetylchitobiose branch of the Escherichia coli phosphotransferase system." J Biol Chem 285(6);4173-84. PMID: 19959833

Jung12: Jung YS, Cai M, Clore GM (2012). "Solution structure of the IIAChitobiose-HPr complex of the N,N'-diacetylchitobiose branch of the Escherichia coli phosphotransferase system." J Biol Chem 287(28);23819-29. PMID: 22593574

Kachroo07: Kachroo AH, Kancherla AK, Singh NS, Varshney U, Mahadevan S (2007). "Mutations that alter the regulation of the chb operon of Escherichia coli allow utilization of cellobiose." Mol Microbiol 66(6);1382-95. PMID: 18028317

Keyhani00a: Keyhani N, Rodgers ME, Demeler B, Hansen JC, Roseman S (2000). "Analytical sedimentation of the IIAChb and IIBChb proteins of the Escherichia coli N,N'-diacetylchitobiose phosphotransferase system. Demonstration of a model phosphotransfer transition state complex." J Biol Chem 275(42);33110-5. PMID: 10913122

Keyhani00b: Keyhani NO, Bacia K, Roseman S (2000). "The transport/phosphorylation of N,N'-diacetylchitobiose in Escherichia coli. Characterization of phospho-IIB(Chb) and of a potential transition state analogue in the phosphotransfer reaction between the proteins IIA(Chb) AND IIB(Chb)." J Biol Chem 275(42);33102-9. PMID: 10913119

Keyhani00c: Keyhani NO, Boudker O, Roseman S (2000). "Isolation and characterization of IIAChb, a soluble protein of the enzyme II complex required for the transport/phosphorylation of N, N'-diacetylchitobiose in Escherichia coli." J Biol Chem 275(42);33091-101. PMID: 10913118

Keyhani00d: Keyhani NO, Wang LX, Lee YC, Roseman S (2000). "The chitin disaccharide, N,N'-diacetylchitobiose, is catabolized by Escherichia coli and is transported/phosphorylated by the phosphoenolpyruvate:glycose phosphotransferase system." J Biol Chem 275(42);33084-90. PMID: 10913117

Keyhani97: Keyhani NO, Roseman S (1997). "Wild-type Escherichia coli grows on the chitin disaccharide, N,N'-diacetylchitobiose, by expressing the cel operon." Proc Natl Acad Sci U S A 1997;94(26);14367-71. PMID: 9405618

Kricker84: Kricker M, Hall BG (1984). "Directed evolution of cellobiose utilization in Escherichia coli K12." Mol Biol Evol 1(2);171-82. PMID: 6400650

Kricker87: Kricker M, Hall BG (1987). "Biochemical genetics of the cryptic gene system for cellobiose utilization in Escherichia coli K12." Genetics 115(3);419-29. PMID: 3552873

Parker90: Parker LL, Hall BG (1990). "Characterization and nucleotide sequence of the cryptic cel operon of Escherichia coli K12." Genetics 124(3);455-71. PMID: 2179047

Parker90a: Parker LL, Hall BG (1990). "Mechanisms of activation of the cryptic cel operon of Escherichia coli K12." Genetics 1990;124(3);473-82. PMID: 2179048

Plumbridge04: Plumbridge J, Pellegrini O (2004). "Expression of the chitobiose operon of Escherichia coli is regulated by three transcription factors: NagC, ChbR and CAP." Mol Microbiol 52(2);437-49. PMID: 15066032

Reizer90: Reizer J, Reizer A, Saier MH (1990). "The cellobiose permease of Escherichia coli consists of three proteins and is homologous to the lactose permease of Staphylococcus aureus." Res Microbiol 1990;141(9);1061-7. PMID: 2092358

Saier14: Saier MH, Reddy VS, Tamang DG, Vastermark A (2014). "The transporter classification database." Nucleic Acids Res 42(1);D251-8. PMID: 24225317

Strauss75: Strauss E (1975). "Sir William Petty." Br Med J 1(5948);30-2. PMID: 1091322

Tang05a: Tang C, Williams DC, Ghirlando R, Clore GM (2005). "Solution structure of enzyme IIA(Chitobiose) from the N,N'-diacetylchitobiose branch of the Escherichia coli phosphotransferase system." J Biol Chem 280(12);11770-80. PMID: 15654077

UniProt09: UniProt Consortium (2009). "UniProt version 15.8 released on 2009-10-01 00:00:00." Database.

UniProt10: UniProt Consortium (2010). "UniProt version 2010-11 released on 2010-11-02 00:00:00." Database.

UniProt10a: UniProt Consortium (2010). "UniProt version 2010-07 released on 2010-06-15 00:00:00." Database.

UniProtGOA11: UniProt-GOA (2011). "Gene Ontology annotation based on manual assignment of UniProtKB keywords in UniProtKB/Swiss-Prot entries."

UniProtGOA11a: UniProt-GOA (2011). "Gene Ontology annotation based on the manual assignment of UniProtKB Subcellular Location terms in UniProtKB/Swiss-Prot entries."

Other References Related to Gene Regulation

Oberto10: Oberto J (2010). "FITBAR: a web tool for the robust prediction of prokaryotic regulons." BMC Bioinformatics 11;554. PMID: 21070640

Overgaard09: Overgaard M, Johansen J, Moller-Jensen J, Valentin-Hansen P (2009). "Switching off small RNA regulation with trap-mRNA." Mol Microbiol 73(5);790-800. PMID: 19682266

Plumbridge14: Plumbridge J, Bossi L, Oberto J, Wade JT, Figueroa-Bossi N (2014). "Interplay of transcriptional and small RNA-dependent control mechanisms regulates chitosugar uptake in Escherichia coli and Salmonella." Mol Microbiol. PMID: 24593230

Zheng04: Zheng D, Constantinidou C, Hobman JL, Minchin SD (2004). "Identification of the CRP regulon using in vitro and in vivo transcriptional profiling." Nucleic Acids Res 32(19);5874-93. PMID: 15520470


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Please cite the following article in publications resulting from the use of EcoCyc: Nucleic Acids Research 41:D605-12 2013
Page generated by SRI International Pathway Tools version 18.5 on Sun Nov 23, 2014, biocyc13.