Escherichia coli K-12 substr. MG1655 Protein: biotin carboxyl carrier protein (dimer)

Gene: accB Accession Numbers: EG10275 (EcoCyc), b3255, ECK3242

Synonyms: fabE, [acetyl-CoA:carbon-dioxide ligase (ADP forming)], BCCP-biotin (monomer), biotin-BCCP (monomer), BCCP

Regulation Summary Diagram: ?

Regulation summary diagram for accB

Component of: acetyl-CoA carboxylase (extended summary available)

Subunit composition of biotin carboxyl carrier protein (dimer) = [AccB]2
         biotinylated biotin-carboxyl carrier protein = AccB

Alternative forms of biotinylated biotin-carboxyl carrier protein: biotin carboxyl carrier protein (extended summary available)

Alternative forms of biotin carboxyl carrier protein (dimer): carboxybiotin-carboxyl-carrier protein

Biotin carboxyl carrier protein (BCCP) plays a central role in the acetyl-CoA carboxylase complex. The overall carboxylase reaction takes place in two distinct half-reactions. BCCP, which contains a biotinyl prosthetic group covalently attached to a specific lysyl residue, is carboxylated in the first partial reaction. In the second partial reaction the carboxyl group is transferred to an acceptor and BCCP is regenerated for further carboxylation [Sutton77]. On the other hand, BCCP amino terminal is able to bind to DNA; this means, BCCP autoregulates its coding gene expression (the accBD operon) [James04].

Citations: [Blanchard99]

Gene Citations: [Karow92, Li93]

Locations: cytosol

Map Position: [3,403,458 -> 3,403,928] (73.36 centisomes, 264°)
Length: 471 bp / 156 aa

Molecular Weight of Polypeptide: 16.687 kD (from nucleotide sequence)

Unification Links: ASAP:ABE-0010675 , CGSC:796 , EchoBASE:EB0271 , EcoGene:EG10275 , OU-Microarray:b3255 , PortEco:accB , RefSeq:NP_417721 , RegulonDB:EG10275

Relationship Links: Pfam:IN-FAMILY:PF00364

Reactions known to consume the compound:

biotin-carboxyl carrier protein assembly :
2 a biotinylated [BCCP monomer] → a biotinylated [BCCP dimer]
a [biotin-carboxyl-carrier protein monomer] + biotin + ATP → AMP + a biotinylated [BCCP monomer] + diphosphate + H+

biotin-carboxyl carrier protein assembly :
a [biotin-carboxyl-carrier protein monomer] + biotin + ATP → AMP + a biotinylated [BCCP monomer] + diphosphate + H+

Reactions known to consume the compound:

biotin-carboxyl carrier protein assembly :
a biotinylated [BCCP dimer] + hydrogen carbonate + ATP → a carboxylated-biotinylated [BCCP dimer] + ADP + phosphate + H+

Reactions known to produce the compound:

biotin-carboxyl carrier protein assembly :
ATP + acetyl-CoA + a carboxylated-biotinylated [BCCP dimer] + H2O → malonyl-CoA + a biotinylated [BCCP dimer] + ADP + phosphate + H+
2 a biotinylated [BCCP monomer] → a biotinylated [BCCP dimer]

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Genetic Regulation Schematic: ?

Genetic regulation schematic for accB

GO Terms:

Biological Process: GO:0006633 - fatty acid biosynthetic process Inferred from experiment [Dimroth70]
Molecular Function: GO:0009374 - biotin binding Inferred from experiment [Sutton77]
Cellular Component: GO:0009317 - acetyl-CoA carboxylase complex Inferred from experiment [Dimroth70]

MultiFun Terms: metabolism biosynthesis of macromolecules (cellular constituents) large molecule carriers biotin carboxyl carrier protein

Symmetry: Inverted Repeat

Regulated Transcription Units (1 total): ?


Transcription-unit diagram

Essentiality data for accB knockouts: ?

Growth Medium Growth? T (°C) O2 pH Osm/L Growth Observations
LB Lennox No 37 Aerobic 7   No [Baba06, Comment 1]

Subunit of: acetyl-CoA carboxylase

Subunit composition of acetyl-CoA carboxylase = [(AccA)2(AccD)2][(AccC)2][(AccB)2]
         acetyl-CoA carboxyltransferase = (AccA)2(AccD)2 (extended summary available)
                 acetyl-CoA carboxyltransferase, α subunit = AccA (summary available)
                 acetyl-CoA carboxyltransferase, β subunit = AccD (summary available)
         biotin carboxylase = (AccC)2
         biotin carboxyl carrier protein (dimer) = (AccB)2 (summary available)
                 biotinylated biotin-carboxyl carrier protein = AccB

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 enzyme belongs to the family of enzymes that catalyze the intermolecular transfer of carboxyl groups via the transient formation of a carboxyphosphate intermediate covalently linked to a biotin prosthetic group [Barber05]. For a thorough discussion of this protein, please see the pathway biotin-carboxyl carrier protein assembly.

The E. coli 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 (dimer) (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].

Coordinated overexpression of accA, accB, accC and accD increases the biosynthesis of fatty acids [Davis00].

Review: [Cronan02a]

GO Terms:

Molecular Function: GO:0003989 - acetyl-CoA carboxylase activity Inferred from experiment [Soriano06]

Enzymatic reaction of: acetyl-CoA carboxylase

EC Number:

ATP + acetyl-CoA + hydrogen carbonate <=> malonyl-CoA + ADP + phosphate + H+

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.

The reaction is physiologically favored in the direction shown.

In Pathways: superpathway of fatty acid biosynthesis I (E. coli) , superpathway of fatty acid biosynthesis initiation (E. coli) , fatty acid biosynthesis initiation I

Acetyl-CoA carboxylase is inhibited by acylated derivatives of ACP. The inhibition is of a mixed type, i.e. a combination of competitive and noncompetitive inhibition. The competitive nature of the inhibition suggests an interaction with the acetyl-CoA binding site. This in turn suggests that the acyl-ACP is binding with the acetyl-CoA carboxyltransferase component of the enzyme complex. [Davis01]

Cofactors or Prosthetic Groups: biotin

Inhibitors (Other): an apo-[acyl-carrier protein] [Davis01]

Inhibitors (Unknown Mechanism): regulatory protein P-II; regulation of nitrogen metabolism and fatty acid biosynthesis [Gerhardt14]

Kinetic Parameters:

Km (μM)

Gene Local Context (not to scale): ?

Gene local context diagram

Transcription Unit:

Transcription-unit diagram


10/20/97 Gene b3255 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG10275; confirmed by SwissProt match.


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

Barber05: Barber MC, Price NT, Travers MT (2005). "Structure and regulation of acetyl-CoA carboxylase genes of metazoa." Biochim Biophys Acta 1733(1);1-28. PMID: 15749055

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

Cronan02a: Cronan JE, Waldrop GL (2002). "Multi-subunit acetyl-CoA carboxylases." Prog Lipid Res 41(5);407-35. PMID: 12121720

Davis00: Davis MS, Solbiati J, Cronan JE (2000). "Overproduction of acetyl-CoA carboxylase activity increases the rate of fatty acid biosynthesis in Escherichia coli." J Biol Chem 275(37);28593-8. PMID: 10893421

Davis01: Davis MS, Cronan, Jr. JE (2001). "Inhibition of Escherichia coli acetyl coenzyme A carboxylase by acyl-acyl carrier protein." J Bacteriol. 183(4):1499-503. PMID: 11157970

Dimroth70: Dimroth P, Guchhait RB, Stoll E, Lane MD (1970). "Enzymatic carboxylation of biotin: molecular and catalytic properties of a component enzyme of acetyl CoA carboxylase." Proc Natl Acad Sci U S A 67(3);1353-60. PMID: 4922289

Gerhardt14: Gerhardt EC, Rodrigues TE, Muller-Santos M, Pedrosa FO, Souza EM, Forchhammer K, Huergo LF (2014). "The Bacterial signal transduction protein GlnB regulates the committed step in fatty acid biosynthesis by acting as a dissociable regulatory subunit of acetyl-CoA carboxylase." Mol Microbiol. PMID: 25557370

James04: James ES, Cronan JE (2004). "Expression of two Escherichia coli acetyl-CoA carboxylase subunits is autoregulated." J Biol Chem 279(4);2520-7. PMID: 14594796

Karow92: Karow M, Fayet O, Georgopoulos C (1992). "The lethal phenotype caused by null mutations in the Escherichia coli htrB gene is suppressed by mutations in the accBC operon, encoding two subunits of acetyl coenzyme A carboxylase." J Bacteriol 174(22);7407-18. PMID: 1358874

Li93: Li SJ, Cronan JE (1993). "Growth rate regulation of Escherichia coli acetyl coenzyme A carboxylase, which catalyzes the first committed step of lipid biosynthesis." J Bacteriol 1993;175(2);332-40. PMID: 7678242

Soriano06: Soriano A, Radice AD, Herbitter AH, Langsdorf EF, Stafford JM, Chan S, Wang S, Liu YH, Black TA (2006). "Escherichia coli acetyl-coenzyme A carboxylase: characterization and development of a high-throughput assay." Anal Biochem 349(2);268-76. PMID: 16325142

Sutton77: Sutton MR, Fall RR, Nervi AM, Alberts AW, Vagelos PR, Bradshaw RA (1977). "Amino acid sequence of Escherichia coli biotin carboxyl carrier protein (9100)." J Biol Chem 1977;252(11);3934-40. PMID: 324999

Other References Related to Gene Regulation

Li92a: Li SJ, Cronan JE (1992). "The gene encoding the biotin carboxylase subunit of Escherichia coli acetyl-CoA carboxylase." J Biol Chem 267(2);855-63. PMID: 1370469

Vanet93: Vanet A, Plumbridge JA, Alix JH (1993). "Cotranscription of two genes necessary for ribosomal protein L11 methylation (prmA) and pantothenate transport (panF) in Escherichia coli K-12." J Bacteriol 1993;175(22);7178-88. PMID: 8226664

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of EcoCyc: Nucleic Acids Research 41:D605-12 2013
Page generated by SRI International Pathway Tools version 19.0 on Fri Oct 9, 2015, biocyc13.