KEGG   ENZYME: 4.1.99.25Help
Entry
EC 4.1.99.25                Enzyme                                 

Name
L-tryptophan isonitrile synthase;
isnA (gene name);
ambI1 (gene name);
well1 (gene name)
Class
Lyases;
Carbon-carbon lyases;
Other carbon-carbon lyases
BRITE hierarchy
Sysname
L-tryptophan:D-ribulose-5-phosphate lyase (isonitrile-forming)
Reaction(IUBMB)
L-tryptophan + D-ribulose 5-phosphate = (2S)-3-(1H-indol-3-yl)-2-isocyanopropanoate + hydroxyacetone + formaldehyde + phosphate + H2O [RN:R12151]
Reaction(KEGG)
Substrate
L-tryptophan [CPD:C00078];
D-ribulose 5-phosphate [CPD:C00199]
Product
(2S)-3-(1H-indol-3-yl)-2-isocyanopropanoate [CPD:C21892];
hydroxyacetone [CPD:C05235];
formaldehyde [CPD:C00067];
phosphate [CPD:C00009];
H2O [CPD:C00001]
Comment
The enzymes from cyanobacteria that belong to the Nostocales order participate in the biosynthesis of hapalindole-type alkaloids. According to the proposed mechanism, the enzyme forms an imine intermediate composed of linked L-tryptophan and D-ribulose 5-phosphate, followed by loss of the phosphate group and formation of a beta-keto imine and keto-enol tautomerization. This is followed by a C-C bond cleavage, the release of hydroxyacetone, and a retro aldol type reaction that releases formaldehyde and forms the final product [3]. cf. EC 4.1.99.24, L-tyrosine isonitrile synthase.
History
EC 4.1.99.25 created 2018
Orthology
K22953  L-tryptophan isonitrile synthase
Reference
1  [PMID:16206308]
  Authors
Brady SF, Clardy J
  Title
Cloning and heterologous expression of isocyanide biosynthetic genes from environmental DNA.
  Journal
Angew Chem Int Ed Engl 44:7063-5 (2005)
DOI:10.1002/anie.200501941
Reference
2  [PMID:16217820]
  Authors
Brady SF, Clardy J
  Title
Systematic investigation of the Escherichia coli metabolome for the biosynthetic  origin of an isocyanide carbon atom.
  Journal
Angew Chem Int Ed Engl 44:7045-8 (2005)
DOI:10.1002/anie.200501942
Reference
3  [PMID:24180436]
  Authors
Hillwig ML, Zhu Q, Liu X
  Title
Biosynthesis of ambiguine indole alkaloids in cyanobacterium Fischerella ambigua.
  Journal
ACS Chem Biol 9:372-7 (2014)
DOI:10.1021/cb400681n
  Sequence
Reference
4  [PMID:28212039]
  Authors
Chang WC, Sanyal D, Huang JL, Ittiamornkul K, Zhu Q, Liu X
  Title
In Vitro Stepwise Reconstitution of Amino Acid Derived Vinyl Isocyanide Biosynthesis: Detection of an Elusive Intermediate.
  Journal
Org Lett 19:1208-1211 (2017)
DOI:10.1021/acs.orglett.7b00258
Other DBs
ExplorEnz - The Enzyme Database: 4.1.99.25
IUBMB Enzyme Nomenclature: 4.1.99.25
ExPASy - ENZYME nomenclature database: 4.1.99.25
BRENDA, the Enzyme Database: 4.1.99.25
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