7KPT

Crystal structure of CtdE in complex with FAD and substrate 4


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.91 Å
  • R-Value Free: 0.201 
  • R-Value Work: 0.170 
  • R-Value Observed: 0.171 

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Ligand Structure Quality Assessment 


This is version 1.1 of the entry. See complete history


Literature

Structural basis of the stereoselective formation of the spirooxindole ring in the biosynthesis of citrinadins.

Liu, Z.Zhao, F.Zhao, B.Yang, J.Ferrara, J.Sankaran, B.Venkataram Prasad, B.V.Kundu, B.B.Phillips Jr., G.N.Gao, Y.Hu, L.Zhu, T.Gao, X.

(2021) Nat Commun 12: 4158-4158

  • DOI: 10.1038/s41467-021-24421-0
  • Primary Citation of Related Structures:  
    7KPQ, 7KPT

  • PubMed Abstract: 
  • Prenylated indole alkaloids featuring spirooxindole rings possess a 3R or 3S carbon stereocenter, which determines the bioactivities of these compounds. Despite the stereoselective advantages of spirooxindole biosynthesis compared with those of organic synthesis, the biocatalytic mechanism for controlling the 3R or 3S-spirooxindole formation has been elusive ...

    Prenylated indole alkaloids featuring spirooxindole rings possess a 3R or 3S carbon stereocenter, which determines the bioactivities of these compounds. Despite the stereoselective advantages of spirooxindole biosynthesis compared with those of organic synthesis, the biocatalytic mechanism for controlling the 3R or 3S-spirooxindole formation has been elusive. Here, we report an oxygenase/semipinacolase CtdE that specifies the 3S-spirooxindole construction in the biosynthesis of 21R-citrinadin A. High-resolution X-ray crystal structures of CtdE with the substrate and cofactor, together with site-directed mutagenesis and computational studies, illustrate the catalytic mechanisms for the possible β-face epoxidation followed by a regioselective collapse of the epoxide intermediate, which triggers semipinacol rearrangement to form the 3S-spirooxindole. Comparing CtdE with PhqK, which catalyzes the formation of the 3R-spirooxindole, we reveal an evolutionary branch of CtdE in specific 3S spirocyclization. Our study provides deeper insights into the stereoselective catalytic machinery, which is important for the biocatalysis design to synthesize spirooxindole pharmaceuticals.


    Organizational Affiliation

    Department of Bioengineering, Rice University, Houston, TX, USA. xue.gao@rice.edu.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
FAD-dependent monooxygenase CtdEA443Penicillium citrinumMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
FAD (Subject of Investigation/LOI)
Query on FAD

Download Ideal Coordinates CCD File 
B [auth A]FLAVIN-ADENINE DINUCLEOTIDE
C27 H33 N9 O15 P2
VWWQXMAJTJZDQX-UYBVJOGSSA-N
 Ligand Interaction
WU4 (Subject of Investigation/LOI)
Query on WU4

Download Ideal Coordinates CCD File 
C [auth A](6aR,7aS,11S,13aS)-6,6,11-trimethyl-4-(3-methylbut-2-en-1-yl)-6,6a,7,8,9,10,11,14-octahydro-5H,13H-13a,7a-(epiminomethano)quinolizino[2,3-b]carbazol-16-one
C28 H37 N3 O
OMTRTWVJZBEAAJ-AEQSLLNGSA-N
 Ligand Interaction
EDO
Query on EDO

Download Ideal Coordinates CCD File 
D [auth A]1,2-ETHANEDIOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
 Ligand Interaction
CL
Query on CL

Download Ideal Coordinates CCD File 
E [auth A]CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.91 Å
  • R-Value Free: 0.201 
  • R-Value Work: 0.170 
  • R-Value Observed: 0.171 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 157.279α = 90
b = 48.527β = 114.488
c = 67.643γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2021-06-16
    Type: Initial release
  • Version 1.1: 2021-07-28
    Changes: Database references