Escherichia coli K-12 substr. MG1655 Polypeptide: sorbitol PTS permease - SrlB subunit

Gene: srlB Accession Numbers: EG10970 (EcoCyc), b2704, ECK2699

Synonyms: gutB, enzyme IIA component of sorbitol PTS, Enzyme IIIsorbitol

Regulation Summary Diagram: ?

Regulation summary diagram for srlB

Component of: sorbitol PTS permease (extended summary available)

Contains a PTS Enzyme IIA (formerly Enzyme III) domain. The hydropathic profile of SrlB is typical of a soluble protein. SrlB may possess a net negative charge at neutral pH as predicted from it's amino acid sequence [Yamada87]

Gene Citations: [McEntee77, Yamada88]

Locations: cytosol

Map Position: [2,825,384 -> 2,825,755] (60.9 centisomes, 219°)
Length: 372 bp / 123 aa

Molecular Weight of Polypeptide: 13.304 kD (from nucleotide sequence), 13.5 kD (experimental) [Yamada87a ]

Unification Links: ASAP:ABE-0008894 , CGSC:11886 , EchoBASE:EB0963 , EcoGene:EG10970 , EcoliWiki:b2704 , OU-Microarray:b2704 , PortEco:srlB , PR:PRO_000023984 , Protein Model Portal:P05706 , RefSeq:NP_417184 , RegulonDB:EG10970 , SMR:P05706 , String:511145.b2704 , Swiss-Model:P05706 , UniProt:P05706

Relationship Links: InterPro:IN-FAMILY:IPR004716 , InterPro:IN-FAMILY:IPR018454 , Pfam:IN-FAMILY:PF03829 , ProDom:IN-FAMILY:PD015842 , Prosite:IN-FAMILY:PS51097

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Genetic Regulation Schematic: ?

Genetic regulation schematic for srlB

GO Terms:

Biological Process: GO:0009401 - phosphoenolpyruvate-dependent sugar phosphotransferase system Inferred from experiment Inferred by computational analysis [UniProtGOA11a, GOA01a, Yamada87a]
GO:0006810 - transport Inferred by computational analysis [UniProtGOA11a]
GO:0008643 - carbohydrate transport Inferred by computational analysis [UniProtGOA11a]
GO:0016310 - phosphorylation Inferred by computational analysis [UniProtGOA11a]
GO:0034219 - carbohydrate transmembrane transport Inferred by computational analysis [GOA01a]
Molecular Function: GO:0016301 - kinase activity Inferred from experiment Inferred by computational analysis [UniProtGOA11a, Yamada87a]
GO:0008982 - protein-N(PI)-phosphohistidine-sugar phosphotransferase activity Inferred by computational analysis [GOA01a]
GO:0016740 - transferase activity Inferred by computational analysis [UniProtGOA11a]
Cellular Component: GO:0005737 - cytoplasm Inferred by computational analysis [UniProtGOA11, UniProtGOA11a, GOA01a, Yamada87]
GO:0005829 - cytosol Inferred by computational analysis [DiazMejia09]

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

Essentiality data for srlB 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]
Yes [Feist07, Comment 3]

Subunit of: sorbitol PTS permease

Synonyms: EIIGut, Enzyme IIGut, glucitol PTS permease

Subunit composition of sorbitol PTS permease = [SrlA][SrlB][SrlE]
         sorbitol PTS permease - SrlA subunit = SrlA (summary available)
         sorbitol PTS permease - SrlB subunit = SrlB (summary available)
         sorbitol PTS permease - SrlE subunit = SrlE (summary available)

SrlABE, also known as GutABE, is the sorbitol PTS permease which belongs to the functional superfamily of the phosphoenolpyruvate (PEP)-dependent, sugar transporting phosphotransferase system (PTSsugar). The PTSsugar transports and simultaneously phosphorylates its sugar substrates in a process called group translocation. SrlAB takes up exogenous sorbitol, releasing the phosphate ester into the cell cytoplasm in preparation for oxidation to fructose-6-P and subsequent metabolism, primarily via glycolysis (reviewed in [Postma93]).

SrlABE comprises the Enzyme IISrl complex. The enzyme possesses a split IIC domain unlike all other characterized Enzyme II complexes of the PTS [Postma93]. SrlA is predicted to be an inner membrane protein containing 4 transmembrane (TM) regions. SrlE is a larger protein of 319 residues that includes the hydrophilic IIB domain fused to a hydrophobic domain containing 4 (putative) TM regions [Reizer96a]. SrlB is the hydrophilic IIA domain. Thus, the integral membrane IIC constituent of the sorbitol permease is split in half and encoded by two distinct genes, srlA and srlE. srlB and srlE, respectively, encode the IIA and IIB constituents. The IIB domain of SrlE and the IIA (SrlB) protein are localized to the cytoplasmic side of the membrane. SrlABE is a member of the PTS Glucitol (Gut) family of transporters [Saier14].

The overall PTS-mediated phosphoryl transfer reaction, requiring the two general energy coupling proteins of the PTS, Enzyme I (PtsI) and HPr (PtsH), as well as the three domains of the Enzyme IIsorbitol complex can be represented by:

PEP → Enzyme I-Phis189 → HPr-Phis15 → EnzymeIIA-Phis43 → Enzyme IIB-Pcys71-(Enyzme IIC) → sorbitol-6-P.

The srl operon is induced by sorbitol and SrlABE transports sorbitol with low micromolar affinities. SrlABE also transports D-mannitol but D-mannitol is not an inducer [Lengeler75a]. A strain containing mutations in mtlA (Enzyme IImannitol), gatA (Enzyme IIdulcitol) and srlA is unable to transport any of the three naturally occuring hexitols - mannitol, dulcitol or sorbitol [Lengeler75].

The srl operon (srlAEBDgutMsrlRgutQ) contains the srlA, srlE and srlB genes, encoding the Enzyme IISrl complex, and the srlD gene encoding sorbitol-6-P dehydrogenase that oxidizes sorbitol-6-P to fructose-6-P. GutM and SrlR are positive and negative transcriptional regulators of srl operon expression, respectively [Yamada88]. gutQ encodes a D-arabinose-5-phosphate isomerase. gut operon expression is under the control of the cyclic AMP-cyclic AMP receptor protein (CRP) complex.

Citations: [McEntee77, Nguyen06]

GO Terms:

Biological Process: GO:0009401 - phosphoenolpyruvate-dependent sugar phosphotransferase system Inferred from experiment [Yamada87a]
Molecular Function: GO:0090565 - protein-phosphocysteine-mannitol phosphotransferase system transporter activity Inferred by computational analysis Inferred from experiment [Lengeler75a, Reizer96a]
GO:0090583 - protein-phosphocysteine-D-sorbitol-phosphotransferase system transporter activity Inferred by computational analysis Inferred from experiment [Lengeler75a, Reizer96a]

Last-Curated ? 25-Jun-2013 by Mackie A , Macquarie University

Enzymatic reaction of: transport and phosphorylation of D-sorbitol (sorbitol PTS permease)

Transport reaction diagram for transport and phosphorylation of D-sorbitol

Kinetic Parameters:

Km (μM)

Enzymatic reaction of: transport and phosphorylation of D-mannitol (sorbitol PTS permease)

Transport reaction diagram for transport and phosphorylation of D-mannitol

Kinetic Parameters:

Km (μM)

Sequence Features

Protein sequence of sorbitol PTS permease - SrlB subunit with features indicated

Feature Class Location Citations Comment
Conserved-Region 3 -> 116
UniProt: PTS EIIA type-5;
Extrinsic-Sequence-Variant 17
UniProt: In strain: ECOR 6, ECOR 28, ECOR 35, ECOR 37, ECOR 51, ECOR 58, ECOR 61, ECOR 66 and ECOR 69..
Active-Site 43
UniProt: Tele-phosphohistidine intermediate; Non-Experimental Qualifier: by similarity;
Extrinsic-Sequence-Variant 51
UniProt: In strain: ECOR 58..
Extrinsic-Sequence-Variant 59
UniProt: In strain: ECOR 28, ECOR 37, ECOR 58 and ECOR 69..
Extrinsic-Sequence-Variant 62
UniProt: In strain: ECOR 51..
Extrinsic-Sequence-Variant 92
UniProt: In strain: ECOR 51, ECOR 61 and ECOR 66..
Sequence-Conflict 122
[Yamamoto97, UniProt10a]
UniProt: (in Ref. 3);

Gene Local Context (not to scale): ?

Gene local context diagram

Transcription Units:

Transcription-unit diagram

Transcription-unit diagram


10/20/97 Gene b2704 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG10970; confirmed by SwissProt match.


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

Feist07: Feist AM, Henry CS, Reed JL, Krummenacker M, Joyce AR, Karp PD, Broadbelt LJ, Hatzimanikatis V, Palsson BO (2007). "A genome-scale metabolic reconstruction for Escherichia coli K-12 MG1655 that accounts for 1260 ORFs and thermodynamic information." Mol Syst Biol 3;121. PMID: 17593909

GOA01a: GOA, DDB, FB, MGI, ZFIN (2001). "Gene Ontology annotation through association of InterPro records with GO terms."

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

Lengeler75: Lengeler J (1975). "Mutations affecting transport of the hexitols D-mannitol, D-glucitol, and galactitol in Escherichia coli K-12: isolation and mapping." J Bacteriol 1975;124(1);26-38. PMID: 1100602

Lengeler75a: Lengeler J (1975). "Nature and properties of hexitol transport systems in Escherichia coli." J Bacteriol 124(1);39-47. PMID: 1100608

McEntee77: McEntee K (1977). "Genetic analysis of the Escherichia coli K-12 srl region." J Bacteriol 1977;132(3);904-11. PMID: 336611

Nguyen06: Nguyen TX, Yen MR, Barabote RD, Saier MH (2006). "Topological predictions for integral membrane permeases of the phosphoenolpyruvate:sugar phosphotransferase system." J Mol Microbiol Biotechnol 11(6);345-60. PMID: 17114898

Postma93: Postma PW, Lengeler JW, Jacobson GR (1993). "Phosphoenolpyruvate:carbohydrate phosphotransferase systems of bacteria." Microbiol Rev 57(3);543-94. PMID: 8246840

Reizer96a: Reizer J, Mitchell WJ, Minton N, Brehm J, Reizer A, Saier MH (1996). "Proposed topology of the glucitol permeases of Escherichia coli and Clostridium acetobutylicum." Curr Microbiol 1996;33(5);331-3. PMID: 8875915

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

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

UniProt10: UniProt Consortium (2010). "UniProt version 2010-07 released on 2010-06-15 00:00:00." Database.

UniProt10a: UniProt Consortium (2010). "UniProt version 2010-11 released on 2010-11-02 00:00:00." Database.

UniProt15: UniProt Consortium (2015). "UniProt version 2015-01 released on 2015-01-16 00:00:00." Database.

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

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

Yamada87: Yamada M, Saier MH (1987). "Glucitol-specific enzymes of the phosphotransferase system in Escherichia coli. Nucleotide sequence of the gut operon." J Biol Chem 1987;262(12);5455-63. PMID: 3553176

Yamada87a: Yamada M, Saier MH (1987). "Physical and genetic characterization of the glucitol operon in Escherichia coli." J Bacteriol 169(7);2990-4. PMID: 3036766

Yamada88: Yamada M, Saier MH (1988). "Positive and negative regulators for glucitol (gut) operon expression in Escherichia coli." J Mol Biol 1988;203(3);569-83. PMID: 3062173

Yamamoto97: Yamamoto Y, Aiba H, Baba T, Hayashi K, Inada T, Isono K, Itoh T, Kimura S, Kitagawa M, Makino K, Miki T, Mitsuhashi N, Mizobuchi K, Mori H, Nakade S, Nakamura Y, Nashimoto H, Oshima T, Oyama S, Saito N, Sampei G, Satoh Y, Sivasundaram S, Tagami H, Horiuchi T (1997). "Construction of a contiguous 874-kb sequence of the Escherichia coli -K12 genome corresponding to 50.0-68.8 min on the linkage map and analysis of its sequence features." DNA Res 4(2);91-113. PMID: 9205837

Other References Related to Gene Regulation

Beisel11: Beisel CL, Storz G (2011). "The base-pairing RNA spot 42 participates in a multioutput feedforward loop to help enact catabolite repression in Escherichia coli." Mol Cell 41(3);286-97. PMID: 21292161

WhiteZiegler07: White-Ziegler CA, Malhowski AJ, Young S (2007). "Human body temperature (37degrees C) increases the expression of iron, carbohydrate, and amino acid utilization genes in Escherichia coli K-12." J Bacteriol 189(15);5429-40. PMID: 17526711

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
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