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Overview for MACiE Entry M0073

Version history

General Information

EC Number: 4.2.1.96 (A member of the Lyases, Carbon-oxygen lyases, Hydro-lyases)

Enzyme Name: 4a-hydroxytetrahydrobiopterin dehydratase

Biological Species: Rattus norvegicus (Rat)

Catalytic Chain UniprotKB Accession Codes:

  • P61459 - Pterin-4-alpha-carbinolamine dehydratase

Representative PDB Code: 1dco - DCOH, A BIFUNCTIONAL PROTEIN-BINDING TRANSCRIPTIONALCOACTIVATOR (Resolution = 2.30 Å).

Catalytic CATH Codes:

Display structure information

Overall Reaction:

Image of 4a((R)-hydroxy-6(S)-methyl-tetrahydropterin

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Image of quinoid dihydrobiopterin

Image of water

4a((R)-hydroxy-6(S)-methyl-tetrahydropterin
C15522
quinoid dihydrobiopterin
C00268
CHEBI:20680
water
C00001
CHEBI:15377

Overall Comment: His 62 is replaced by His 80 for the 4a(S),6(R) diastereoisomer.


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Stepwise Description of the Reaction

Step 1His63 deprotonates the substrate initiating a double bond rearrangement that forms an oxyanion.
Step 2The substrate eliminates water, which obtains its proton from His62.
Step 3His62 deprotonates the substrate.
Step 4The oxyanion collapses, initiating double bond rearrangement that results in the deprotonation of His63 and the formation of the final product.

View similar reactions (composite manual annotation)


Catalytic Residues Involved

Type Number Chain Location of Function
Glu 58 A Side Chain
His 62 A Side Chain
His 63 A Side Chain
His 80 A Main Chain Amide
Glu 81 A Main Chain Amide
Asp 89 A Side Chain

References

  1. J. D. Cronk et al. (1996), Protein Sci., 5, 1963-1972. High-resolution structures of the bifunctional enzyme and transcriptional coactivator DCoH and its complex with a product analogue.
    Medline: 8897596
  2. I. Rebrin et al. (1998), Biochemistry, 37, 11246-11254. Stereospecificity and catalytic function of histidine residues in 4a-hydroxy-tetrahydropterin dehydratase/DCoH.
    Medline: 9698371

Homologue information for M0073 (1dco)

CSA Homologues

MACiE Homologues (within the PDB)

MACiE Homologues (within UniprotKB/SwissProt)


Links to this entry in other databases

Link to EC-PDB-SUM Link to PDB-SUM Link to RCSB PDB Link to PDBe Link to CSA
Link to MetaCyc Link to KEGG Link to BRENDA Link to ExplorENZ
Link to EzCatDB

GOA logo
tetrahydrobiopterin biosynthetic process (biological process)
4-alpha-hydroxytetrahydrobiopterin dehydratase activity (molecular function)
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