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: BCCP assembly
|Superclasses:||Biosynthesis → Fatty Acid and Lipid Biosynthesis|
Some taxa known to possess this pathway include : Aquifex aeolicus , Arabidopsis thaliana col , Bacillus subtilis , Corynebacterium glutamicum , Escherichia coli K-12 substr. MG1655 , Mycobacterium leprae , Mycobacterium tuberculosis , Myxococcus xanthus , Nicotiana tabacum , Pisum sativum , Propionibacterium freudenreichii , Pseudomonas aeruginosa , Ricinus communis
Biotin-dependent carboxylases constitute a group of enzymes with many common features in structure and mechanism [Wood77]. These enzymes have been identified in prokaryotic and eukaryotic organisms. Some members of this family include acetyl-CoA carboxylase, propionyl-CoA carboxylase, pyruvate decarboxylase and the Propionibacterium freudenreichii transcarboxylase [Thornton93]. These enzymes are involved in various metabolic reactions such as lipogenesis, gluconeogenesis, and amino acid metabolism. Another group of bioin-dependent enzymes are the decarboxylases mediating sodium transport [Samols88] (for an example, see biotin-dependent malonate decarboxylase from Malonomonas rubra).
The different biotin-dependent enzymes have different architectures in different organisms. For example, eukaryotic acetyl-CoA carboxylases contain three functional modules in one large polypeptide (biotin carboxylase/biotin-carboxyl-carrier protein/carboxyltransferase), eukaryotic propionyl-CoA-carboxylases and bifunctional acetyl/propionyl-CoA carboxylases of Mycobacteria are composed of a coupled biotin carboxylase/biotin-carboxyl-carrier protein polypeptide and separate carboxyltransferase proteins, while all the subunits of Escherichia coli acetyl-CoA carboxylase exist as single proteins [Toh93, Norman94, Jager96].
About This Pathway
The enzyme acetyl-CoA carboxylase is one of the key enzymes in the biosynthesis of fatty acids (see superpathway of fatty acid biosynthesis initiation (E. coli)). The Escherichia coli K-12 enzyme complex is composed of two catalytic units and one carrier protein, encoded by four different genes. The catalytic units are biotin carboxylase (BC), a homodimer encoded by the accC gene, and acetyl-CoA carboxylase (ACCT), an α2β2 tetramer, encoded by the accA and accD genes. The carrier protein is the biotin carboxyl carrier protein (BCCP), a homodimer encoded by the accB gene.
The BCCP monomer is biotinylated by the enzyme biotin-[acetyl-CoA-carboxylase] ligase. Following dimerization of the biotinylated monomers, biotin carboxylase (BC) catalyzes the addition of CO2 to the carrier protein dimer, forming a carboxylated-biotinylated [BCCP dimer] (carboxy-BCCP). a carboxylated-biotinylated [BCCP dimer] in turn is the substrate for ACCT, which transfers the carboxy group to acetyl-CoA, resulting in the formation of malonyl-CoA and the regeneration of biotin carboxyl carrier protein (dimer). Both biotinylation and carboxylation of the carrier protein require ATP, while the last step, transfer of the carboxy group to acetyl-CoA, does not [Barber05].
The pathway has been summarized by the EC reaction 18.104.22.168 , as follows:
Jager96: Jager W, Peters-Wendisch PG, Kalinowski J, Puhler A (1996). "A Corynebacterium glutamicum gene encoding a two-domain protein similar to biotin carboxylases and biotin-carboxyl-carrier proteins." Arch Microbiol 166(2);76-82. PMID: 8772169
Norman94: Norman E, De Smet KA, Stoker NG, Ratledge C, Wheeler PR, Dale JW (1994). "Lipid synthesis in mycobacteria: characterization of the biotin carboxyl carrier protein genes from Mycobacterium leprae and M. tuberculosis." J Bacteriol 176(9);2525-31. PMID: 7909542
Thornton93: Thornton CG, Kumar GK, Haase FC, Phillips NF, Woo SB, Park VM, Magner WJ, Shenoy BC, Wood HG, Samols D (1993). "Primary structure of the monomer of the 12S subunit of transcarboxylase as deduced from DNA and characterization of the product expressed in Escherichia coli." J Bacteriol 175(17);5301-8. PMID: 8366018
AbdelHamid07a: Abdel-Hamid AM, Cronan JE (2007). "Coordinate expression of the acetyl coenzyme A carboxylase genes, accB and accC, is necessary for normal regulation of biotin synthesis in Escherichia coli." J Bacteriol 189(2);369-76. PMID: 17056747
Alberts69: Alberts AW, Nervi AM, Vagelos PR (1969). "Acetyl CoA carboxylase, II. Deomonstration of biotin-protein and biotin carboxylase subunits." Proc Natl Acad Sci U S A 63(4);1319-26. PMID: 4901473
Arifuzzaman06: Arifuzzaman M, Maeda M, Itoh A, Nishikata K, Takita C, Saito R, Ara T, Nakahigashi K, Huang HC, Hirai A, Tsuzuki K, Nakamura S, Altaf-Ul-Amin M, Oshima T, Baba T, Yamamoto N, Kawamura T, Ioka-Nakamichi T, Kitagawa M, Tomita M, Kanaya S, Wada C, Mori H (2006). "Large-scale identification of protein-protein interaction of Escherichia coli K-12." Genome Res 16(5);686-91. PMID: 16606699
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
Barker81a: Barker DF, Campbell AM (1981). "Genetic and biochemical characterization of the birA gene and its product: evidence for a direct role of biotin holoenzyme synthetase in repression of the biotin operon in Escherichia coli." J Mol Biol 146(4);469-92. PMID: 6456358
Benson08: Benson BK, Meades G, Grove A, Waldrop GL (2008). "DNA inhibits catalysis by the carboxyltransferase subunit of acetyl-CoA carboxylase: implications for active site communication." Protein Sci 17(1);34-42. PMID: 18156466
Bilder06: Bilder P, Lightle S, Bainbridge G, Ohren J, Finzel B, Sun F, Holley S, Al-Kassim L, Spessard C, Melnick M, Newcomer M, Waldrop GL (2006). "The structure of the carboxyltransferase component of acetyl-coA carboxylase reveals a zinc-binding motif unique to the bacterial enzyme." Biochemistry 45(6);1712-22. PMID: 16460018
Blanchard99: Blanchard CZ, Chapman-Smith A, Wallace JC, Waldrop GL (1999). "The biotin domain peptide from the biotin carboxyl carrier protein of Escherichia coli acetyl-CoA carboxylase causes a marked increase in the catalytic efficiency of biotin carboxylase and carboxyltransferase relative to free biotin." J Biol Chem 1999;274(45);31767-9. PMID: 10542197
Blanchard99a: Blanchard CZ, Amspacher D, Strongin R, Waldrop GL (1999). "Inhibition of biotin carboxylase by a reaction intermediate analog: implications for the kinetic mechanism." Biochem Biophys Res Commun 1999;266(2);466-71. PMID: 10600526
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