|Gene:||pgaB||Accession Numbers: G6530 (EcoCyc), b1023, ECK1013|
Synonyms: hmsF, ycdR
The pgaABCD locus is required for the synthesis of a cell-bound hexosamine-rich polysaccharide, which was identified as a linear polymer of beta-1,6-N-acetylglucosamine residues (PGA), an adhesin essential in biofilm formation [Wang04a, Itoh05]. PgaB is involved in the transport of PGA across the outer membrane and is involved in biofilm formation. The PgaB protein belongs to the carbohydrate esterase family 4 and contains putative polysaccharide N-deacetylase domains. N-deacetylation of PGA by PgaB promotes its transport across the outer membrane. PgaB is a predicted lipoprotein.
A pgaB mutant has reduced biofilm formation [Wang04a]. pgaB mutants do not release significant amounts of PGA into the medium during shaking at 26 C compared to wild-type, though they are able to release some PGA at 37 C [Itoh08]. PGA from pgaB mutants is not externally exposed showing PgaB is involved in transport of PGA across the outer membrane [Itoh08]. Mutation of the deacetylase reaction site of PgaB prevents export of PGA and biofilm formation [Itoh08]. Analysis of free amino groups in PGA from pgaB+ strains and pgaB mutants reveals that PgaB is responsible for N-deacetylation of PGA [Itoh08].
Expression of pgaABCD is higher at 37 C than at 21 C and is highest during stationary phase [Cerca08]. Expression also increased in response to one-percent NaCl or ethanol [Cerca08]. Expression increased in response to glucose, ethanol, NaCl, and MnCl2 in a clinical isolate, and dramatically increased upon deletion or mutation of csrA in this strain [Cerca08, Mercante06]. CsrA inhibits translation of pgaABCD mRNA by binding to six sites within the pgaABCD leader [Wang05c, Mercante06]. NaCl and alkaline pH induction are dependent upon nhaR as deletion of this gene prevented induction [Goller06, Cerca08].
PgaB has similarity to the HmsF protein encoded by the Yersinia pestis hmsHFRST gene cluster, which is involved in plague transmission [Jones99d].
Locations: outer membrane
|Map Position: [1,087,062 <- 1,089,080] (23.43 centisomes)||Length: 2019 bp / 672 aa|
Molecular Weight of Polypeptide: 77.413 kD (from nucleotide sequence)
Unification Links: ASAP:ABE-0003467 , DIP:DIP-11513N , EchoBASE:EB3624 , EcoGene:EG13864 , EcoliWiki:b1023 , ModBase:P75906 , OU-Microarray:b1023 , PortEco:pgaB , Protein Model Portal:P75906 , RefSeq:NP_415542 , RegulonDB:G6530 , SMR:P75906 , String:511145.b1023 , UniProt:P75906
Relationship Links: InterPro:IN-FAMILY:IPR002509 , InterPro:IN-FAMILY:IPR011330 , InterPro:IN-FAMILY:IPR023854 , PDB:Structure:3VUS , PDB:Structure:4F9D , PDB:Structure:4F9J , Pfam:IN-FAMILY:PF01522 , Prosite:IN-FAMILY:PS51257 , Prosite:IN-FAMILY:PS51677
|Biological Process:||GO:0042710 - biofilm formation
GO:0005975 - carbohydrate metabolic process [GOA01a]
|Molecular Function:||GO:0016810 - hydrolase activity, acting on carbon-nitrogen (but not peptide) bonds
GO:0003824 - catalytic activity [GOA01a]
GO:0016787 - hydrolase activity [UniProtGOA11a]
|Cellular Component:||GO:0009279 - cell outer membrane
GO:0016020 - membrane [UniProtGOA11a]
|MultiFun Terms:||metabolism → biosynthesis of macromolecules (cellular constituents)|
|Growth Medium||Growth?||T (°C)||O2||pH||Osm/L||Growth Observations|
|LB enriched||Yes||37||Aerobic||6.95||Yes [Gerdes03, Comment 1]|
|LB Lennox||Yes||37||Aerobic||7||Yes [Baba06, Comment 2]|
|M9 medium with 1% glycerol||Yes||37||Aerobic||7.2||0.35||Yes [Joyce06, Comment 3]|
|MOPS medium with 0.4% glucose||Yes||37||Aerobic||7.2||0.22||Yes [Baba06, Comment 2]|
Enzymatic reaction of: poly-β-1,6-N-acetyl-D-glucosamine N-deacetylase
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.
Reversibility of this reaction is unspecified.
|Feature Class||Location||Common Name||Citations||Comment|
|Signal-Sequence||1 -> 20||PgaB signal sequence|
|Chain||21 -> 672|
|Lipid-Binding-Site||21||PgaB palmitoylation site|
|Conserved-Region||107 -> 349|
Markus Krummenacker on Tue Oct 14, 1997:
Gene object created from Blattner lab Genbank (v. M52) entry.
Agladze05: Agladze K, Wang X, Romeo T (2005). "Spatial periodicity of Escherichia coli K-12 biofilm microstructure initiates during a reversible, polar attachment phase of development and requires the polysaccharide adhesin PGA." J Bacteriol 187(24);8237-46. PMID: 16321928
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
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
Goller06: Goller C, Wang X, Itoh Y, Romeo T (2006). "The cation-responsive protein NhaR of Escherichia coli activates pgaABCD transcription, required for production of the biofilm adhesin poly-beta-1,6-N-acetyl-D-glucosamine." J Bacteriol 188(23);8022-32. PMID: 16997959
Itoh05: Itoh Y, Wang X, Hinnebusch BJ, Preston JF, Romeo T (2005). "Depolymerization of beta-1,6-N-acetyl-D-glucosamine disrupts the integrity of diverse bacterial biofilms." J Bacteriol 187(1);382-7. PMID: 15601723
Itoh08: Itoh Y, Rice JD, Goller C, Pannuri A, Taylor J, Meisner J, Beveridge TJ, Preston JF, Romeo T (2008). "Roles of pgaABCD genes in synthesis, modification, and export of the Escherichia coli biofilm adhesin poly-beta-1,6-N-acetyl-D-glucosamine." J Bacteriol 190(10);3670-80. PMID: 18359807
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
Mercante06: Mercante J, Suzuki K, Cheng X, Babitzke P, Romeo T (2006). "Comprehensive alanine-scanning mutagenesis of Escherichia coli CsrA defines two subdomains of critical functional importance." J Biol Chem 281(42);31832-42. PMID: 16923806
Wang04a: Wang X, Preston JF, Romeo T (2004). "The pgaABCD locus of Escherichia coli promotes the synthesis of a polysaccharide adhesin required for biofilm formation." J Bacteriol 186(9);2724-34. PMID: 15090514
Wang05c: Wang X, Dubey AK, Suzuki K, Baker CS, Babitzke P, Romeo T (2005). "CsrA post-transcriptionally represses pgaABCD, responsible for synthesis of a biofilm polysaccharide adhesin of Escherichia coli." Mol Microbiol 56(6);1648-63. PMID: 15916613
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