Escherichia coli K-12 substr. MG1655 Enzyme: Fad I component of anaerobic fatty acid oxidation complex

Gene: fadI Accession Numbers: G7213 (EcoCyc), b2342, ECK2336

Synonyms: yfcY

Regulation Summary Diagram

Regulation summary diagram for fadI

Component of: anaerobic fatty acid oxidation complex (summary available)

Subunit composition of Fad I component of anaerobic fatty acid oxidation complex = [FadI]2
         FadI monomer = FadI

During anaerobic beta-oxidation of fatty acids FadI, FadJ, and FadK serve functions parallel to those of FadA, FadB, and FadD in the aerobic pathway [Campbell03].

FadJ and FadI exhibit partial functional redundancy with FadA and FadB under aerobic conditions and the two complexes are proposed to increase efficiency of the process by favoring substrates of different chain length [Campbell03].

A strain producing FadJ and FadI from a plasmid exhibits thiolase activity with beta-ketyoacyl-CoAs of 6 to 12 carbon units but not with acetoacetyl-CoA [Snell02]. FadJ and FadI copurify over a gel filtration column [Snell02].

Regulation has been described [Campbell03]. FadR represses transcription of yfcYX in the presence of oxygen [Campbell03].

Locations: cytosol

Map Position: [2,457,181 <- 2,458,491] (52.96 centisomes, 191°)
Length: 1311 bp / 436 aa

Molecular Weight of Polypeptide: 46.531 kD (from nucleotide sequence)

Unification Links: ASAP:ABE-0007725, DIP:DIP-11991N, EchoBASE:EB3880, EcoGene:EG14128, EcoliWiki:b2342, ModBase:P76503, OU-Microarray:b2342, PortEco:fadI, Pride:P76503, Protein Model Portal:P76503, RefSeq:NP_416844, RegulonDB:G7213, SMR:P76503, String:511145.b2342, Swiss-Model:P76503, UniProt:P76503

Relationship Links: InterPro:IN-FAMILY:IPR002155, InterPro:IN-FAMILY:IPR012806, InterPro:IN-FAMILY:IPR016039, InterPro:IN-FAMILY:IPR020610, InterPro:IN-FAMILY:IPR020613, InterPro:IN-FAMILY:IPR020615, InterPro:IN-FAMILY:IPR020616, InterPro:IN-FAMILY:IPR020617, Panther:IN-FAMILY:PTHR18919, Pfam:IN-FAMILY:PF00108, Pfam:IN-FAMILY:PF02803, Prosite:IN-FAMILY:PS00098, Prosite:IN-FAMILY:PS00099, Prosite:IN-FAMILY:PS00737

In Paralogous Gene Group: 286 (5 members)

Gene-Reaction Schematic

Gene-Reaction Schematic

Instance reaction of [a cis-3-enoyl-CoA ↔ a trans-2-enoyl-CoA] (
i2: 3-cis-dodecenoyl-CoA = trans-dodec-2-enoyl-CoA (

Instance reaction of [a (3S)-3-hydroxyacyl-CoA + NAD+ → a 3-oxoacyl-CoA + NADH + H+] (
i1: 3-hydroxy-5-cis-tetradecenoyl-CoA + NAD+ = 3-keto-5-cis-tetradecenoyl-CoA + NADH + H+ (

Genetic Regulation Schematic

Genetic regulation schematic for fadI

GO Terms:
Biological Process:
Inferred from experimentGO:0033542 - fatty acid beta-oxidation, unsaturated, even number [Campbell03]
Inferred by computational analysisGO:0006629 - lipid metabolic process [UniProtGOA11a]
Inferred by computational analysisGO:0006631 - fatty acid metabolic process [UniProtGOA11a, GOA06, GOA01]
Inferred by computational analysisGO:0006635 - fatty acid beta-oxidation [UniProtGOA12]
Inferred by computational analysisGO:0008152 - metabolic process [GOA01]
Inferred by computational analysisGO:0016042 - lipid catabolic process [UniProtGOA11a, GOA06, GOA01]
Molecular Function:
Inferred from experimentGO:0003857 - 3-hydroxyacyl-CoA dehydrogenase activity [Snell02]
Inferred from experimentInferred by computational analysisGO:0003988 - acetyl-CoA C-acyltransferase activity [GOA06, GOA01a, Snell02]
Inferred from experimentGO:0004300 - enoyl-CoA hydratase activity [Snell02]
Inferred by computational analysisGO:0003824 - catalytic activity [GOA01]
Inferred by computational analysisGO:0016740 - transferase activity [UniProtGOA11a]
Inferred by computational analysisGO:0016746 - transferase activity, transferring acyl groups [UniProtGOA11a, GOA01]
Inferred by computational analysisGO:0016747 - transferase activity, transferring acyl groups other than amino-acyl groups [GOA01]
Cellular Component:
Inferred from experimentInferred by computational analysisGO:0005737 - cytoplasm [UniProtGOA11, UniProtGOA11a, GOA06, GOA01, Snell02]
Inferred from experimentInferred by computational analysisGO:0005829 - cytosol [DiazMejia09, Ishihama08]

MultiFun Terms: metabolismcarbon utilizationfatty acids

Essentiality data for fadI knockouts:

Growth Medium Growth? T (°C) O2 pH Osm/L Growth Observations
LB enrichedYes 37 Aerobic 6.95   Yes [Gerdes03, Comment 1]
LB LennoxYes 37 Aerobic 7   Yes [Baba06, Comment 2]
M9 medium with 1% glycerolYes 37 Aerobic 7.2 0.35 Yes [Joyce06, Comment 3]
MOPS medium with 0.4% glucoseYes 37 Aerobic 7.2 0.22 Yes [Baba06, Comment 2]
Yes [Feist07, Comment 4]

Enzymatic reaction of: acetyl-CoA C-acyltransferase (Fad I component of anaerobic fatty acid oxidation complex)

Inferred by computational analysisInferred from experiment

Synonyms: acyl-CoA:acetyl-CoA C-acyltransferase

EC Number:

a 2,3,4-saturated fatty acyl CoA + acetyl-CoA ← a 3-oxoacyl-CoA + coenzyme A

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the Enzyme Commission system.

The reaction is physiologically favored in the opposite direction.

In Pathways: fatty acid β-oxidation I

Subunit of: anaerobic fatty acid oxidation complex

Subunit composition of anaerobic fatty acid oxidation complex = [(FadJ)2][(FadI)2]
         FadJ component of anaerobic fatty acid oxidation complex = (FadJ)2
                 FadJ monomer = FadJ
         Fad I component of anaerobic fatty acid oxidation complex = (FadI)2
                 FadI monomer = FadI

During anaerobic beta-oxidation of fatty acids FadI, FadJ, and FadK serve functions parallel to those of FadA, FadB, and FadD in the aerobic pathway [Campbell03].

Sequence Features

Protein sequence of FadI monomer with features indicated

Feature Class Location Citations Comment
Pfam PF00108 15 -> 288
Inferred by computational analysis[Finn14]
Thiolase_N : Thiolase, N-terminal domain
Active-Site 99
Inferred by computational analysis[UniProt15]
UniProt: Acyl-thioester intermediate.
Pfam PF02803 297 -> 434
Inferred by computational analysis[Finn14]
Thiolase_C : Thiolase, C-terminal domain
Active-Site 392
Inferred by computational analysis[UniProt15]
UniProt: Proton acceptor.
Active-Site 422
Inferred by computational analysis[UniProt15]
UniProt: Proton acceptor.

Gene Local Context (not to scale -- see Genome Browser for correct scale)

Gene local context diagram

Transcription Unit

Transcription-unit diagram


Markus Krummenacker on Tue Oct 14, 1997:
Gene object created from Blattner lab Genbank (v. M52) entry.


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

Campbell03: Campbell JW, Morgan-Kiss RM, E Cronan J (2003). "A new Escherichia coli metabolic competency: growth on fatty acids by a novel anaerobic beta-oxidation pathway." Mol Microbiol 47(3);793-805. PMID: 12535077

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

Feist07: Feist AM, Henry CS, Reed JL, Krummenacker M, Joyce AR, Karp PD, Broadbelt LJ, Hatzimanikatis V, Palsson BO (2007). "A genome-scale metabolic reconstruction for Escherichia coli K-12 MG1655 that accounts for 1260 ORFs and thermodynamic information." Mol Syst Biol 3;121. PMID: 17593909

Finn14: Finn RD, Bateman A, Clements J, Coggill P, Eberhardt RY, Eddy SR, Heger A, Hetherington K, Holm L, Mistry J, Sonnhammer EL, Tate J, Punta M (2014). "Pfam: the protein families database." Nucleic Acids Res 42(Database issue);D222-30. PMID: 24288371

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

GOA01: GOA, DDB, FB, MGI, ZFIN (2001). "Gene Ontology annotation through association of InterPro records with GO terms."

GOA01a: GOA, MGI (2001). "Gene Ontology annotation based on Enzyme Commission mapping." Genomics 74;121-128.

GOA06: GOA, SIB (2006). "Electronic Gene Ontology annotations created by transferring manual GO annotations between orthologous microbial proteins."

Ishihama08: Ishihama Y, Schmidt T, Rappsilber J, Mann M, Hartl FU, Kerner MJ, Frishman D (2008). "Protein abundance profiling of the Escherichia coli cytosol." BMC Genomics 9;102. PMID: 18304323

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

Snell02: Snell KD, Feng F, Zhong L, Martin D, Madison LL (2002). "YfcX enables medium-chain-length poly(3-hydroxyalkanoate) formation from fatty acids in recombinant Escherichia coli fadB strains." J Bacteriol 184(20);5696-705. PMID: 12270828

UniProt15: UniProt Consortium (2015). "UniProt version 2015-08 released on 2015-07-22." Database.

UniProtGOA11: UniProt-GOA (2011). "Gene Ontology annotation based on the manual assignment of UniProtKB Subcellular Location terms in UniProtKB/Swiss-Prot entries."

UniProtGOA11a: UniProt-GOA (2011). "Gene Ontology annotation based on manual assignment of UniProtKB keywords in UniProtKB/Swiss-Prot entries."

UniProtGOA12: UniProt-GOA (2012). "Gene Ontology annotation based on UniPathway vocabulary mapping."

Other References Related to Gene Regulation

Cho06: Cho BK, Knight EM, Palsson BO (2006). "Transcriptional regulation of the fad regulon genes of Escherichia coli by ArcA." Microbiology 152(Pt 8);2207-19. PMID: 16849788

Huerta03: Huerta AM, Collado-Vides J (2003). "Sigma70 promoters in Escherichia coli: specific transcription in dense regions of overlapping promoter-like signals." J Mol Biol 333(2);261-78. PMID: 14529615

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
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