|Gene:||acpS||Accession Numbers: EG10247 (MetaCyc), b2563, ECK2561|
Species: Escherichia coli K-12 substr. MG1655
Subunit composition of holo-[acyl-carrier-protein] synthase = [AcpS]2
The acpS gene encodes holo-[ACP] synthase, which transfers the 4-phosphopantetheine moiety of CoA to the apo-ACP to form holo-ACP, the active form of the carrier in lipid synthesis [Lambalot95, Elovson68, Polacco81]. The enzyme is an AcpS homodimer [Lambalot95].
The acpS gene is essential for viability [Takiff92, Lam92]. An acpS mutant exhibits growth dependence on supplementation of the media with high levels of pantothenate [Polacco81]. Decreased holo-ACP abundance does not affect the rate of incorporation of oleic acid into phospholipid [Cronan84]. A conditional acpS mutant (MP4 strain) exhibits an abnormally low ratio of holo-ACP to apo-ACP under permissive as well as restrictive conditions, whereas the ratio of phospholipid to protein content is similar to wild type, indicating that the holo-ACP to apo-ACP ratio is not critical for the maintenance of lipid abundance [Jackowski83]. This conditional acpS1 mutation from the MP4 strain specifies a G4D change, which decreases enzyme efficiency by 5-fold [Flugel00]. The heat sensitivity of an acpS1 mutant is suppressed by overproduction of YhhU [Flugel00]. Suppressors of acpS reduction-of-function mutations include lon mutations [Lam92].
AcpS is a member of a 4'-phosphopantetheinyl transferase (P-pant transferase, or PPTase) protein family (including E. coli EntD, E. coli o195 protein, and Bacillus subtilis Sfp) that shares two conserved motifs but shares relatively low sequence identity overall [Lambalot96]. The phenotype of an E. coli acpS mutant is functionally complemented by Streptococcus pneumoniae AcpS [McAllister00], Bacillus subtilis AcpS (encoded by ydcB) [Mootz01], Bacillus subtilis Sfp [Mootz01], or Bacillus brevis Gsp [Mootz01].
Regulation has been described [Matsunaga96].
|Map Position: [2,698,640 <- 2,699,020]|
Molecular Weight of Polypeptide: 14.052 kD (from nucleotide sequence)
Unification Links: ASAP:ABE-0008433 , DIP:DIP-9047N , EchoBASE:EB0243 , EcoGene:EG10247 , EcoliWiki:b2563 , Mint:MINT-1256571 , ModBase:P24224 , OU-Microarray:b2563 , PortEco:acpS , PR:PRO_000022046 , Pride:P24224 , Protein Model Portal:P24224 , RefSeq:NP_417058 , RegulonDB:EG10247 , SMR:P24224 , String:511145.b2563 , UniProt:P24224
Instance reactions of [an acyl-carrier protein + coenzyme A → adenosine 3',5'-bisphosphate + a holo-[acyl-carrier protein] + H+] (220.127.116.11):
|Biological Process:||GO:0018070 - peptidyl-serine phosphopantetheinylation
GO:0006629 - lipid metabolic process [UniProtGOA11a]
GO:0006631 - fatty acid metabolic process [UniProtGOA11a]
GO:0006633 - fatty acid biosynthetic process [UniProtGOA11a, GOA06, GOA01a, Lambalot95]
|Molecular Function:||GO:0008897 - holo-[acyl-carrier-protein] synthase activity
[GOA06, GOA01, GOA01a, Lambalot95]
GO:0000287 - magnesium ion binding [GOA06, GOA01a]
GO:0016740 - transferase activity [UniProtGOA11a, Lambalot95]
GO:0046872 - metal ion binding [UniProtGOA11a]
|Cellular Component:||GO:0005737 - cytoplasm
[UniProtGOA11, UniProtGOA11a, GOA06]
GO:0005829 - cytosol [DiazMejia09]
|MultiFun Terms:||metabolism → biosynthesis of building blocks → fatty acids and phosphatidic acid|
Enzymatic reaction of: holo-[acyl-carrier-protein] synthase
Synonyms: CoA:apo-ACP pantetheinephosphotransferase, ACP synthetase, ACPS, holo-ACP synthase
EC Number: 18.104.22.168
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.
The reaction is favored in the direction shown.
The holo-ACP synthase enzyme transfers the 4-phosphopantetheine moeity of CoA to the apo-ACP to form holo-ACP, which is the active form of the carrier in lipid synthesis [Elovson68, Polacco81]. The enzyme is an AcpS homodimer [Lambalot95].
Holo-ACP synthase shows a Km of 50 micromolar for CoA and a Km of less than 1 micromolar for apo-ACP (which becomes inhibitory at higher concentrations, over 2 micromolar) [Lambalot95]. The enzyme favors ACP substrates with greater negative charge in vitro, and it can utilize some analogs of CoA [Gehring97].
Holo-ACP synthase exhibits activity toward various exogenous substrates, including a spinach ACP substrate [Jaworski89, Broadwater99], rat Type I fatty acid synthase ACP domain [Tropf98], Lactobacillus casei D-alanyl carrier protein (Dcp) [Debabov96], Rhizobium NodF [Ritsema98], and Streptomyces spp. polyketide synthase ACPs that catalyze formation of a number of compounds with antibiotic activity such as oxytetracycline [Gehring97], tetracenomycin [Gehring97], granaticin [Gehring97, Carreras97], frenolicin [Gehring97, Carreras97], griseusin [Cox97], and actinorhodin [Cox97, Carreras97]. Holo-ACP synthase also transfers various acylated moieties from acylated CoAs to polyketide synthase ACPs [Cox97, Carreras97].
Holo-ACP synthase has been purified using a denaturation and renaturation step [Lambalot95].
|Chain||2 -> 126|
3/2/1998 (pkarp) Merged genes G220/EG10247 and EG10247/acpS
1/26/1998 (pkarp) Merged genes G7984/acpS and EG10247/dpj
Broadwater99: Broadwater JA, Fox BG (1999). "Spinach holo-acyl carrier protein: overproduction and phosphopantetheinylation in Escherichia coli BL21(DE3), in vitro acylation, and enzymatic desaturation of histidine-tagged isoform I." Protein Expr Purif 15(3);314-26. PMID: 10092491
Carreras97: Carreras CW, Gehring AM, Walsh CT, Khosla C (1997). "Utilization of enzymatically phosphopantetheinylated acyl carrier proteins and acetyl-acyl carrier proteins by the actinorhodin polyketide synthase." Biochemistry 36(39);11757-61. PMID: 9305965
Cox97: Cox RJ, Hitchman TS, Byrom KJ, Findlow IS, Tanner JA, Crosby J, Simpson TJ (1997). "Post-translational modification of heterologously expressed Streptomyces type II polyketide synthase acyl carrier proteins." FEBS Lett 405(3);267-72. PMID: 9108302
Cronan84: Cronan JE (1984). "Evidence that incorporation of exogenous fatty acids into the phospholipids of Escherichia coli does not require acyl carrier protein." J Bacteriol 159(2);773-5. PMID: 6378892
Debabov96: Debabov DV, Heaton MP, Zhang Q, Stewart KD, Lambalot RH, Neuhaus FC (1996). "The D-Alanyl carrier protein in Lactobacillus casei: cloning, sequencing, and expression of dltC." J Bacteriol 178(13);3869-76. PMID: 8682792
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
Flugel00: Flugel RS, Hwangbo Y, Lambalot RH, Cronan JE, Walsh CT (2000). "Holo-(acyl carrier protein) synthase and phosphopantetheinyl transfer in Escherichia coli." J Biol Chem 2000;275(2);959-68. PMID: 10625633
Gehring97: Gehring AM, Lambalot RH, Vogel KW, Drueckhammer DG, Walsh CT (1997). "Ability of Streptomyces spp. acyl carrier proteins and coenzyme A analogs to serve as substrates in vitro for E. coli holo-ACP synthase." Chem Biol 4(1);17-24. PMID: 9070424
Jaworski89: Jaworski JG, Post-Beittenmiller MA, Ohlrogge JB (1989). "Site-directed mutagenesis of the spinach acyl carrier protein-I prosthetic group attachment site." Eur J Biochem 184(3);603-9. PMID: 2553397
Lam92: Lam HM, Tancula E, Dempsey WB, Winkler ME (1992). "Suppression of insertions in the complex pdxJ operon of Escherichia coli K-12 by lon and other mutations." J Bacteriol 1992;174(5);1554-67. PMID: 1537800
Lambalot96: Lambalot RH, Gehring AM, Flugel RS, Zuber P, LaCelle M, Marahiel MA, Reid R, Khosla C, Walsh CT (1996). "A new enzyme superfamily - the phosphopantetheinyl transferases." Chem Biol 1996;3(11);923-36. PMID: 8939709
MAJERUS65: MAJERUS PW, ALBERTS AW, VAGELOS PR (1965). "ACYL CARRIER PROTEIN. IV. THE IDENTIFICATION OF 4'-PHOSPHOPANTETHEINE AS THE PROSTHETIC GROUP OF THE ACYL CARRIER PROTEIN." Proc Natl Acad Sci U S A 53;410-7. PMID: 14294075
McAllister00: McAllister KA, Peery RB, Meier TI, Fischl AS, Zhao G (2000). "Biochemical and molecular analyses of the Streptococcus pneumoniae acyl carrier protein synthase, an enzyme essential for fatty acid biosynthesis." J Biol Chem 275(40);30864-72. PMID: 10903317
McAllister06: McAllister KA, Peery RB, Zhao G (2006). "Acyl carrier protein synthases from gram-negative, gram-positive, and atypical bacterial species: Biochemical and structural properties and physiological implications." J Bacteriol 188(13);4737-48. PMID: 16788183
Ritsema98: Ritsema T, Gehring AM, Stuitje AR, van der Drift KM, Dandal I, Lambalot RH, Walsh CT, Thomas-Oates JE, Lugtenberg BJ, Spaink HP (1998). "Functional analysis of an interspecies chimera of acyl carrier proteins indicates a specialized domain for protein recognition." Mol Gen Genet 257(6);641-8. PMID: 9604887
Takiff92: Takiff HE, Baker T, Copeland T, Chen SM, Court DL (1992). "Locating essential Escherichia coli genes by using mini-Tn10 transposons: the pdxJ operon." J Bacteriol 174(5);1544-53. PMID: 1537799
Tropf98: Tropf S, Revill WP, Bibb MJ, Hopwood DA, Schweizer M (1998). "Heterologously expressed acyl carrier protein domain of rat fatty acid synthase functions in Escherichia coli fatty acid synthase and Streptomyces coelicolor polyketide synthase systems." Chem Biol 5(3);135-46. PMID: 9545424
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