This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
Synonyms: cis vaccenic acid acid biosynthesis
|Superclasses:||Biosynthesis → Fatty Acid and Lipid Biosynthesis → Fatty Acid Biosynthesis → Unsaturated Fatty Acid Biosynthesis|
The only unsaturated fatty acids found in Escherichia coli, palmitoleate and cis-vaccenate, comprise about one-half the fatty acid content of the organism. The proportion of unsaturated fatty acids is known to increase in Escherichia coli with lower growth temperature, a phenomenon found in most organisms that provides a mechanism for adjusting the lipid phase transition of the membrane phospholipids to differing temperatures.
KASII is the only enzyme that can catalyze the conversion of palmitoleate to cis-vaccenate, and is believed to play a major role in the thermal regulation of fatty acid composition of the membrane phospholipids of Escherichia coli [Garwin80a]. KASII is one of three β-ketoacyl-ACP synthases (KAS) in Escherichia coli: KASI, KASII and KASIII, encoded by fabB, fabF and fabH, respectively.
It has been shown that KASII is more active at low temperatures (relative to the overall rate of fatty acid synthesis) than at high temperatures [Garwin80]. This relative increase results in the production of cis-vaccenate rather than palmitoleate. Furthermore, because the former (but not the later) can be incorporated into both positions of sn-glycerol 3-phosphate, the synthesis of diunsaturated phospholipids occurs and the thermotrophic phase transition of the membrane phospholipids is lowered [Garwin80a].
Some plant species such as Asclepias syriaca and Dolichandra unguis-cati (Doxantha unguis-cati L.) produce relatively high levels of palmitoleate and cis-vaccenate in their seed oils [Chisholm60, Chisholm65]. The plastidal synthesis of cis-vaccenate from palmitoleate via KASII is thought to be similar to that of the Escherichia coli pathway (in [Nguyen10b]). KAS II enzymes (EC 22.214.171.124) have been characterized in Brassica napus [Han01a] and Spinacia oleracea [Shimakata82], and a NADH-dependent enoyl-ACP reductase (EC 126.96.36.199) has been characterized in these and several other plant species [Shimakata82, Kater91, Caughey82, Shimakata82a].
Unification Links: EcoCyc:PWY-5973
Caughey82: Caughey I, Kekwick RG (1982). "The characteristics of some components of the fatty acid synthetase system in the plastids from the mesocarp of avocado (Persea americana) fruit." Eur J Biochem 123(3);553-61. PMID: 7075600
Garwin80: Garwin JL, Klages AL, Cronan JE (1980). "Structural, enzymatic, and genetic studies of beta-ketoacyl-acyl carrier protein synthases I and II of Escherichia coli." J Biol Chem 1980;255(24);11949-56. PMID: 7002930
Garwin80a: Garwin JL, Klages AL, Cronan JE (1980). "Beta-ketoacyl-acyl carrier protein synthase II of Escherichia coli. Evidence for function in the thermal regulation of fatty acid synthesis." J Biol Chem 1980;255(8);3263-5. PMID: 6988423
Han01a: Han J, Luhs W, Sonntag K, Zahringer U, Borchardt DS, Wolter FP, Heinz E, Frentzen M (2001). "Functional characterization of beta-ketoacyl-CoA synthase genes from Brassica napus L." Plant Mol Biol 46(2);229-39. PMID: 11442062
Kater91: Kater MM, Koningstein GM, Nijkamp HJ, Stuitje AR (1991). "cDNA cloning and expression of Brassica napus enoyl-acyl carrier protein reductase in Escherichia coli." Plant Mol Biol 17(4);895-909. PMID: 1912503
Nguyen10b: Nguyen HT, Mishra G, Whittle E, Pidkowich MS, Bevan SA, Merlo AO, Walsh TA, Shanklin J (2010). "Metabolic engineering of seeds can achieve levels of omega-7 fatty acids comparable with the highest levels found in natural plant sources." Plant Physiol 154(4);1897-904. PMID: 20943853
Shimakata82: Shimakata T, Stumpf PK (1982). "Purification and characterizations of beta-Ketoacyl-[acyl-carrier-protein] reductase, beta-hydroxyacyl-[acyl-carrier-protein] dehydrase, and enoyl-[acyl-carrier-protein] reductase from Spinacia oleracea leaves." Arch Biochem Biophys 218(1);77-91. PMID: 6756317
Shimakata82a: Shimakata T, Stumpf PK (1982). "The procaryotic nature of the fatty acid synthetase of developing Carthamus tinctorius L. (Safflower) seeds." Arch Biochem Biophys 217(1);144-54. PMID: 7125663
Baldock96: Baldock C, Rafferty JB, Sedelnikova SE, Baker PJ, Stuitje AR, Slabas AR, Hawkes TR, Rice DW (1996). "A mechanism of drug action revealed by structural studies of enoyl reductase." Science 274(5295);2107-10. PMID: 8953047
Barnes68: Barnes EM, Wakil SJ (1968). "Studies on the mechanism of fatty acid synthesis. XIX. Preparation and general properties of palmityl thioesterase." J Biol Chem 1968;243(11);2955-62. PMID: 4871199
Bergler94: Bergler H, Wallner P, Ebeling A, Leitinger B, Fuchsbichler S, Aschauer H, Kollenz G, Hogenauer G, Turnowsky F (1994). "Protein EnvM is the NADH-dependent enoyl-ACP reductase (FabI) of Escherichia coli." J Biol Chem 1994;269(8);5493-6. PMID: 8119879
Bergler96: Bergler H, Fuchsbichler S, Hogenauer G, Turnowsky F (1996). "The enoyl-[acyl-carrier-protein] reductase (FabI) of Escherichia coli, which catalyzes a key regulatory step in fatty acid biosynthesis, accepts NADH and NADPH as cofactors and is inhibited by palmitoyl-CoA." Eur J Biochem 242(3);689-94. PMID: 9022698
Butland05: Butland G, Peregrin-Alvarez JM, Li J, Yang W, Yang X, Canadien V, Starostine A, Richards D, Beattie B, Krogan N, Davey M, Parkinson J, Greenblatt J, Emili A (2005). "Interaction network containing conserved and essential protein complexes in Escherichia coli." Nature 433(7025);531-7. PMID: 15690043
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
Edwards97: Edwards P, Nelsen JS, Metz JG, Dehesh K (1997). "Cloning of the fabF gene in an expression vector and in vitro characterization of recombinant fabF and fabB encoded enzymes from Escherichia coli." FEBS Lett 402(1);62-6. PMID: 9013860
Escaich11: Escaich S, Prouvensier L, Saccomani M, Durant L, Oxoby M, Gerusz V, Moreau F, Vongsouthi V, Maher K, Morrissey I, Soulama-Mouze C (2011). "The MUT056399 inhibitor of FabI is a new antistaphylococcal compound." Antimicrob Agents Chemother 55(10);4692-7. PMID: 21825292
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