Escherichia coli K-12 substr. MG1655 Protein: capsular polysaccharide export apparatus
Inferred from experiment

Subunit composition of capsular polysaccharide export apparatus = [Wza]8[Wzc]4
         lipoprotein required for capsular polysaccharide translocation through the outer membrane = Wza (extended summary available)
         protein-tyrosine kinase = Wzc (extended summary available)

Citations: [Collins07]

Gene-Reaction Schematic

Gene-Reaction Schematic

Created 11-Apr-2007 by Johnson A, TIGR

Subunit of capsular polysaccharide export apparatus: lipoprotein required for capsular polysaccharide translocation through the outer membrane

Synonyms: Wza

Gene: wza Accession Numbers: G7107 (EcoCyc), b2062, ECK2056

Locations: outer membrane

Sequence Length: 379 AAs

Molecular Weight: 41.91 kD (from nucleotide sequence)

GO Terms:
Biological Process:
Inferred by computational analysisGO:0000271 - polysaccharide biosynthetic process [UniProtGOA11a]
Inferred by computational analysisGO:0006810 - transport [UniProtGOA11a]
Inferred by computational analysisGO:0006811 - ion transport [UniProtGOA11a]
Inferred by computational analysisGO:0008643 - carbohydrate transport [UniProtGOA11a]
Inferred by computational analysisGO:0015774 - polysaccharide transport [UniProtGOA11a, GOA01a]
Inferred by computational analysisGO:0055085 - transmembrane transport [UniProtGOA11a]
Molecular Function:
Inferred by computational analysisGO:0015159 - polysaccharide transmembrane transporter activity [GOA01a]
Inferred by computational analysisGO:0015288 - porin activity [UniProtGOA11a]
Cellular Component:
Inferred by computational analysisGO:0009279 - cell outer membrane [UniProtGOA11, UniProtGOA11a, DiazMejia09]
Inferred by computational analysisGO:0016020 - membrane [UniProtGOA11a, GOA01a]
Inferred by computational analysisGO:0016021 - integral component of membrane [UniProtGOA11a]
Inferred by computational analysisGO:0046930 - pore complex [UniProtGOA11a]

MultiFun Terms: metabolismbiosynthesis of macromolecules (cellular constituents)colanic acid (M antigen)
transportPutative uncharacterized transport protein

Unification Links: DIP:DIP-11134N, EcoliWiki:b2062, Pride:P0A930, Protein Model Portal:P0A930, RefSeq:NP_416566, SMR:P0A930, UniProt:P0A930

Relationship Links: InterPro:IN-FAMILY:IPR003715, InterPro:IN-FAMILY:IPR019554, Pfam:IN-FAMILY:PF02563, Pfam:IN-FAMILY:PF10531, Prosite:IN-FAMILY:PS51257

Based on sequence similarity, Wza is a member of the outer membrane auxiliary (OMA) protein family [Paulsen97]. Much of the information known about Wza comes from experiments examining Wza of Escherichia coli serotype K30 (WzaK30), though wza from E. coli K-12 can complement a wza defect in E. coli K30 [Reid05].

WzaK30 is a surface exposed outer membrane lipoprotein that forms a multimeric 'secretin-like' structure [Drummelsmith99, Drummelsmith00]. Insertional inactivation of wza in E. coli strain E69 serotype O9a:K30 results in loss of the K30 capsular layer although K30 polysaccharide is still produced [Drummelsmith99]. WzaK30 forms ring-like octameric structures arranged as tetramers of dimers [Nesper03, Beis04, Beis04a]. WzaK30 contains a transmembrane domain that is a novel α-helical barrel structure and a large periplasmic domain that forms the bulk of the structure. The protein has a large central cavity that is open to the extracellular region [Dong06].

WzaK30 is believed to form the outer membrane translocation channel for K30 capsular antigen. K30 polysaccharide intermediates have been trapped and identified in the interior of multimeric Wza structures [Nickerson14].

WzaK30 forms a complex with WzcK30 [Nesper03, Collins07]. The periplasmic domain of WzaK30 interacts with the periplasmic domain of WzcK30 [Collins07].

Reviews: [Collins07a]

Citations: [Ford09]

Essentiality data for wza knockouts:

Growth Medium Growth? T (°C) O2 pH Osm/L Growth Observations
LB enrichedYes 37 Aerobic 6.95   Yes [Gerdes03, Comment 1]
LB LennoxYes 37 Aerobic 7   Yes [Baba06, Comment 2]
M9 medium with 1% glycerolYes 37 Aerobic 7.2 0.35 Yes [Joyce06, Comment 3]
MOPS medium with 0.4% glucoseYes 37 Aerobic 7.2 0.22 Yes [Baba06, Comment 2]

Component enzyme of capsular polysaccharide export apparatus : protein-tyrosine kinase

Synonyms: Wzc

Gene: wzc Accession Numbers: G7105 (EcoCyc), b2060, ECK2054

Locations: inner membrane

Sequence Length: 720 AAs

Molecular Weight: 79.343 kD (from nucleotide sequence)

Molecular Weight: 80.0 kD (experimental) [Vincent00a]

GO Terms:
Biological Process:
Inferred from experimentGO:0009242 - colanic acid biosynthetic process [Vincent00a]
Inferred from experimentGO:0018108 - peptidyl-tyrosine phosphorylation [Grangeasse02]
Inferred from experimentGO:0038083 - peptidyl-tyrosine autophosphorylation [Vincent99]
Inferred by computational analysisGO:0000271 - polysaccharide biosynthetic process [UniProtGOA11a]
Inferred by computational analysisGO:0009103 - lipopolysaccharide biosynthetic process [GOA01a]
Inferred by computational analysisGO:0016310 - phosphorylation [UniProtGOA11a]
Inferred by computational analysisGO:0045226 - extracellular polysaccharide biosynthetic process [GOA01a]
Molecular Function:
Inferred from experimentInferred by computational analysisGO:0004713 - protein tyrosine kinase activity [UniProtGOA11a, Vincent99]
Inferred from experimentGO:0016887 - ATPase activity [Soulat07]
Inferred by computational analysisGO:0000166 - nucleotide binding [UniProtGOA11a]
Inferred by computational analysisGO:0005524 - ATP binding [UniProtGOA11a]
Inferred by computational analysisGO:0016301 - kinase activity [UniProtGOA11a]
Inferred by computational analysisGO:0016740 - transferase activity [UniProtGOA11a]
Cellular Component:
Inferred from experimentInferred by computational analysisGO:0005886 - plasma membrane [UniProtGOA11, UniProtGOA11a, DiazMejia09, Daley05]
Inferred from experimentGO:0005887 - integral component of plasma membrane [Doublet02]
Inferred from experimentInferred by computational analysisGO:0016020 - membrane [UniProtGOA11a, GOA01a, Vincent00a]
Inferred by computational analysisGO:0016021 - integral component of membrane [UniProtGOA11a]

MultiFun Terms: information transferprotein relatedposttranslational modification
metabolismbiosynthesis of macromolecules (cellular constituents)colanic acid (M antigen)

Unification Links: DIP:DIP-28075N, EcoliWiki:b2060, Mint:MINT-8293229, ModBase:P76387, PR:PRO_000024223, Pride:P76387, Protein Model Portal:P76387, RefSeq:NP_416564, SMR:P76387, UniProt:P76387

Relationship Links: InterPro:IN-FAMILY:IPR003856, InterPro:IN-FAMILY:IPR005702, InterPro:IN-FAMILY:IPR025669, InterPro:IN-FAMILY:IPR027417, PDB:Structure:3LA6, Pfam:IN-FAMILY:PF02706, Pfam:IN-FAMILY:PF13614, Pfam:IN-FAMILY:PF13807

ATP + a [protein]-L-tyrosine → ADP + a [protein]-L-tyrosine phosphate + H+

Wzc is a protein-tyrosine kinase that catalyzes autophosphorylation on tyrosine; phosphorylated Wzc can be dephosphorylated by Wzb [Vincent99, Soutourina01]. Autophosphorylation negatively regulates colanic acid biosynthesis [Vincent00a]. However, both the phosphorylated and the nonphosphorylated forms of Wzc are required for wild-type synthesis of colanic acid [Obadia07]. Wzc also catalyzes phosphorylation of Ugd (Ugd, an enzyme of colanic acid biosynthesis), and this phosphorylation stimulates Ugd activity [Grangeasse03].

Wzc consists of an N-terminal domain with two transmembrane α-helices separated by a periplasmic region, and a C-terminal cytoplasmic domain containing six phosphorylation sites [Grangeasse02, Doublet02]. The N-terminal membrane domain appears to have no effect on the extent of phosphorylation of the C-terminal domain [Grangeasse02]. Tyr569 in the C-terminal domain is the substrate for intramolecular autophosphorylation; phosphorylation of this residue activates the kinase activity of Wzc, enabling it to catalyze intermolecular phosphorylation of tyrosine residues 708, 710, 711, 713, and 715 in the C-terminal tyrosine cluster of Wzc [Grangeasse02] and toward Ugd [Grangeasse03]. A Walker A and B ATP-binding motif is present in the C-terminal domain, and Wzc exhibits an ATPase activity that is regulated by intramolecular autophosphorylation [Soulat07].

The C-terminal region mediates formation of homomultimers [Doublet02].

A wzc null mutant does not produce colanic acid [Vincent00a].

Involvement of Wzc in production of the capsule was shown in other E. coli strains, including O9a:K30 [Rahn99, Drummelsmith99, Wugeditsch01, Paiment02]. Cryo-EM experiments show that Wzc from a K30 strain forms homotetramers [Collins06], and Wza and Wzc form a complex [Collins07]. E. coli K-12 Wzc can rescue K30 capsule expression in a mutant O9a:K30 strain only in combination with the cognate K-12 Wza protein [Reid05].

Review: [Whitfield06]

Essentiality data for wzc knockouts:

Growth Medium Growth? T (°C) O2 pH Osm/L Growth Observations
LB enrichedYes 37 Aerobic 6.95   Yes [Gerdes03, Comment 1]
LB LennoxYes 37 Aerobic 7   Yes [Baba06, Comment 2]
M9 medium with 1% glycerolYes 37 Aerobic 7.2 0.35 Yes [Joyce06, Comment 3]
MOPS medium with 0.4% glucoseYes 37 Aerobic 7.2 0.22 Yes [Baba06, Comment 2]


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

Beis04: Beis K, Collins RF, Ford RC, Kamis AB, Whitfield C, Naismith JH (2004). "Three-dimensional structure of Wza, the protein required for translocation of group 1 capsular polysaccharide across the outer membrane of Escherichia coli." J Biol Chem 279(27);28227-32. PMID: 15090537

Beis04a: Beis K, Nesper J, Whitfield C, Naismith JH (2004). "Crystallization and preliminary X-ray diffraction analysis of Wza outer-membrane lipoprotein from Escherichia coli serotype O9a:K30." Acta Crystallogr D Biol Crystallogr 60(Pt 3);558-60. PMID: 14993692

Collins06: Collins RF, Beis K, Clarke BR, Ford RC, Hulley M, Naismith JH, Whitfield C (2006). "Periplasmic protein-protein contacts in the inner membrane protein Wzc form a tetrameric complex required for the assembly of Escherichia coli group 1 capsules." J Biol Chem 281(4);2144-50. PMID: 16172129

Collins07: Collins RF, Beis K, Dong C, Botting CH, McDonnell C, Ford RC, Clarke BR, Whitfield C, Naismith JH (2007). "The 3D structure of a periplasm-spanning platform required for assembly of group 1 capsular polysaccharides in Escherichia coli." Proc Natl Acad Sci U S A 104(7);2390-5. PMID: 17283336

Collins07a: Collins RF, Derrick JP (2007). "Wza: a new structural paradigm for outer membrane secretory proteins?." Trends Microbiol 15(3);96-100. PMID: 17275308

Daley05: Daley DO, Rapp M, Granseth E, Melen K, Drew D, von Heijne G (2005). "Global topology analysis of the Escherichia coli inner membrane proteome." Science 308(5726);1321-3. PMID: 15919996

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

Dong06: Dong C, Beis K, Nesper J, Brunkan-Lamontagne AL, Clarke BR, Whitfield C, Naismith JH (2006). "Wza the translocon for E. coli capsular polysaccharides defines a new class of membrane protein." Nature 444(7116);226-9. PMID: 17086202

Doublet02: Doublet P, Grangeasse C, Obadia B, Vaganay E, Cozzone AJ (2002). "Structural organization of the protein-tyrosine autokinase Wzc within Escherichia coli cells." J Biol Chem 277(40);37339-48. PMID: 12138098

Drummelsmith00: Drummelsmith J, Whitfield C (2000). "Translocation of group 1 capsular polysaccharide to the surface of Escherichia coli requires a multimeric complex in the outer membrane." EMBO J 19(1);57-66. PMID: 10619844

Drummelsmith99: Drummelsmith J, Whitfield C (1999). "Gene products required for surface expression of the capsular form of the group 1 K antigen in Escherichia coli (O9a:K30)." Mol Microbiol 31(5);1321-32. PMID: 10200954

Ford09: Ford RC, Brunkan-Lamontagne AL, Collins RF, Clarke BR, Harris R, Naismith JH, Whitfield C (2009). "Structure-function relationships of the outer membrane translocon Wza investigated by cryo-electron microscopy and mutagenesis." J Struct Biol 166(2):172-82. PMID: 19236919

Gerdes03: Gerdes SY, Scholle MD, Campbell JW, Balazsi G, Ravasz E, Daugherty MD, Somera AL, Kyrpides NC, Anderson I, Gelfand MS, Bhattacharya A, Kapatral V, D'Souza M, Baev MV, Grechkin Y, Mseeh F, Fonstein MY, Overbeek R, Barabasi AL, Oltvai ZN, Osterman AL (2003). "Experimental determination and system level analysis of essential genes in Escherichia coli MG1655." J Bacteriol 185(19);5673-84. PMID: 13129938

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

Grangeasse02: Grangeasse C, Doublet P, Cozzone AJ (2002). "Tyrosine phosphorylation of protein kinase Wzc from Escherichia coli K12 occurs through a two-step process." J Biol Chem 277(9);7127-35. PMID: 11751920

Grangeasse03: Grangeasse C, Obadia B, Mijakovic I, Deutscher J, Cozzone AJ, Doublet P (2003). "Autophosphorylation of the Escherichia coli protein kinase Wzc regulates tyrosine phosphorylation of Ugd, a UDP-glucose dehydrogenase." J Biol Chem 278(41);39323-9. PMID: 12851388

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

Nesper03: Nesper J, Hill CM, Paiment A, Harauz G, Beis K, Naismith JH, Whitfield C (2003). "Translocation of group 1 capsular polysaccharide in Escherichia coli serotype K30. Structural and functional analysis of the outer membrane lipoprotein Wza." J Biol Chem 278(50);49763-72. PMID: 14522970

Nickerson14: Nickerson NN, Mainprize IL, Hampton L, Jones ML, Naismith JH, Whitfield C (2014). "Trapped translocation intermediates establish the route for export of capsular polysaccharides across Escherichia coli outer membranes." Proc Natl Acad Sci U S A 111(22);8203-8. PMID: 24843147

Obadia07: Obadia B, Lacour S, Doublet P, Baubichon-Cortay H, Cozzone AJ, Grangeasse C (2007). "Influence of tyrosine-kinase Wzc activity on colanic acid production in Escherichia coli K12 cells." J Mol Biol 367(1);42-53. PMID: 17254603

Paiment02: Paiment A, Hocking J, Whitfield C (2002). "Impact of phosphorylation of specific residues in the tyrosine autokinase, Wzc, on its activity in assembly of group 1 capsules in Escherichia coli." J Bacteriol 184(23);6437-47. PMID: 12426330

Paulsen97: Paulsen IT, Beness AM, Saier MH (1997). "Computer-based analyses of the protein constituents of transport systems catalysing export of complex carbohydrates in bacteria." Microbiology 143 ( Pt 8);2685-99. PMID: 9274022

Rahn99: Rahn A, Drummelsmith J, Whitfield C (1999). "Conserved organization in the cps gene clusters for expression of Escherichia coli group 1 K antigens: relationship to the colanic acid biosynthesis locus and the cps genes from Klebsiella pneumoniae." J Bacteriol 181(7);2307-13. PMID: 10094716

Reid05: Reid AN, Whitfield C (2005). "functional analysis of conserved gene products involved in assembly of Escherichia coli capsules and exopolysaccharides: evidence for molecular recognition between Wza and Wzc for colanic acid biosynthesis." J Bacteriol 187(15);5470-81. PMID: 16030241

Soulat07: Soulat D, Jault JM, Geourjon C, Gouet P, Cozzone AJ, Grangeasse C (2007). "Tyrosine-kinase Wzc from Escherichia coli possesses an ATPase activity regulated by autophosphorylation." FEMS Microbiol Lett 274(2);252-9. PMID: 17627778

Soutourina01: Soutourina J, Blanquet S, Plateau P (2001). "Role of D-cysteine desulfhydrase in the adaptation of Escherichia coli to D-cysteine." J Biol Chem 276(44);40864-72. PMID: 11527960

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."

Vincent00a: Vincent C, Duclos B, Grangeasse C, Vaganay E, Riberty M, Cozzone AJ, Doublet P (2000). "Relationship between exopolysaccharide production and protein-tyrosine phosphorylation in gram-negative bacteria." J Mol Biol 304(3);311-21. PMID: 11090276

Vincent99: Vincent C, Doublet P, Grangeasse C, Vaganay E, Cozzone AJ, Duclos B (1999). "Cells of Escherichia coli contain a protein-tyrosine kinase, Wzc, and a phosphotyrosine-protein phosphatase, Wzb." J Bacteriol 181(11);3472-7. PMID: 10348860

Whitfield06: Whitfield C (2006). "Biosynthesis and assembly of capsular polysaccharides in Escherichia coli." Annu Rev Biochem 75;39-68. PMID: 16756484

Wugeditsch01: Wugeditsch T, Paiment A, Hocking J, Drummelsmith J, Forrester C, Whitfield C (2001). "Phosphorylation of Wzc, a tyrosine autokinase, is essential for assembly of group 1 capsular polysaccharides in Escherichia coli." J Biol Chem 276(4);2361-71. PMID: 11053445

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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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