KEGG   ENZYME: 4.2.1.175
Entry
EC 4.2.1.175                Enzyme                                 

Name
(R)-3-(aryl)lactoyl-CoA dehydratase;
fldBC (gene names);
(R)-phenyllactoyl-CoA dehydratase;
aryllactyl-CoA dehydratase
Class
Lyases;
Carbon-oxygen lyases;
Hydro-lyases
Sysname
(R)-3-(aryl)lactoyl-CoA hydro-lyase
Reaction(IUBMB)
(1) (R)-3-(phenyl)lactoyl-CoA = (E)-cinnamoyl-CoA + H2O [RN:R12487];
(2) (R)-3-(4-hydroxyphenyl)lactoyl-CoA = (E)-4-coumaroyl-CoA + H2O [RN:R12488];
(3) (R)-3-(indol-3-yl)lactoyl-CoA = 3-(indol-3-yl)acryloyl-CoA + H2O [RN:R12489]
Reaction(KEGG)
Substrate
(R)-3-(phenyl)lactoyl-CoA [CPD:C16257];
(R)-3-(4-hydroxyphenyl)lactoyl-CoA [CPD:C22205];
(R)-3-(indol-3-yl)lactoyl-CoA [CPD:C22206]
Product
(E)-cinnamoyl-CoA [CPD:C16256];
H2O [CPD:C00001];
(E)-4-coumaroyl-CoA [CPD:C00223];
3-(indol-3-yl)acryloyl-CoA [CPD:C22207]
Comment
The enzyme, found in some amino acid-fermenting anaerobic bacteria, participates in the fermentation pathways of L-phenylalanine, L-tyrosine, and L-tryptophan. It is a heterodimeric protein consisting of the FldB and FldC polypeptides, both of which contain an [4Fe-4S] cluster, and forms a complex with EC 2.8.3.17, 3-(aryl)acryloyl-CoA:(R)-3-(aryl)lactate CoA-transferase (FldA). In order to catalyse the reaction, the enzyme requires one high-energy electron that transiently reduces the electrophilic thiol ester carbonyl of the substrate to a nucleophilic ketyl radical anion, facilitating the elimination of the hydroxyl group. This electron, which is provided by by EC 5.6.1.9, (R)-2-hydroxyacyl-CoA dehydratase activating ATPase, needs to be supplied only once, before the first reaction takes place, as it is regenerated at the end of each reaction cycle. The enzyme acts on (R)-3-(aryl)lactoyl-CoAs produced by FldA, and regenerates the CoA donors used by that enzyme.
History
EC 4.2.1.175 created 2019
Orthology
K23110  (R)-3-(aryl)lactoyl-CoA dehydratase alpha subunit
K23111  (R)-3-(aryl)lactoyl-CoA dehydratase beta subunit
Genes
SYM: K6K13_14540
CBO: CBO3289(fldC) CBO3290(fldB)
CBA: CLB_3345(fldC) CLB_3346(fldB)
CBH: CLC_3231(fldC) CLC_3232(fldB)
CBY: CLM_3722(fldC) CLM_3723(fldB)
CBL: CLK_2705(fldC) CLK_2706(fldB)
CBB: CLD_1233(fldB) CLD_1234(fldC)
CBI: CLJ_B3569(fldC) CLJ_B3570(fldB)
CBF: CLI_3459(fldC) CLI_3460(fldB)
CBM: CBF_3441 CBF_3442(fldB)
CLD: CLSPO_c34090(fldC) CLSPO_c34100(fldB)
ACEL: acsn021_19890(fldC)
THYD: TTHT_2111
 » show all
Reference
1  [PMID:10849007]
  Authors
Dickert S, Pierik AJ, Linder D, Buckel W
  Title
The involvement of coenzyme A esters in the dehydration of (R)-phenyllactate to (E)-cinnamate by Clostridium sporogenes.
  Journal
Eur J Biochem 267:3874-84 (2000)
DOI:10.1046/j.1432-1327.2000.01427.x
  Sequence
Reference
2  [PMID:11967068]
  Authors
Dickert S, Pierik AJ, Buckel W
  Title
Molecular characterization of phenyllactate dehydratase and its initiator from Clostridium sporogenes.
  Journal
Mol Microbiol 44:49-60 (2002)
DOI:10.1046/j.1365-2958.2002.02867.x
  Sequence
Reference
3  [PMID:15374661]
  Authors
Kim J, Hetzel M, Boiangiu CD, Buckel W
  Title
Dehydration of (R)-2-hydroxyacyl-CoA to enoyl-CoA in the fermentation of alpha-amino acids by anaerobic bacteria.
  Journal
FEMS Microbiol Rev 28:455-68 (2004)
DOI:10.1016/j.femsre.2004.03.001
Reference
4  [PMID:18337824]
  Authors
Kim J, Darley DJ, Buckel W, Pierik AJ
  Title
An allylic ketyl radical intermediate in clostridial amino-acid fermentation.
  Journal
Nature 452:239-42 (2008)
DOI:10.1038/nature06637
Reference
5  [PMID:29168502]
  Authors
Dodd D, Spitzer MH, Van Treuren W, Merrill BD, Hryckowian AJ, Higginbottom SK, Le A, Cowan TM, Nolan GP, Fischbach MA, Sonnenburg JL
  Title
A gut bacterial pathway metabolizes aromatic amino acids into nine circulating metabolites.
  Journal
Nature 551:648-652 (2017)
DOI:10.1038/nature24661
  Sequence
Other DBs
ExplorEnz - The Enzyme Database: 4.2.1.175
IUBMB Enzyme Nomenclature: 4.2.1.175
ExPASy - ENZYME nomenclature database: 4.2.1.175
BRENDA, the Enzyme Database: 4.2.1.175

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