FlvF from Aspergillus flavus in complex with Bis-Tris

Experimental Data Snapshot

  • Resolution: 2.62 Å
  • R-Value Free: 0.243 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.209 

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Structure of the Repurposed Fungal Terpene Cyclase FlvF Implicated in the C-N Bond-Forming Reaction of Flavunoidine Biosynthesis.

Tararina, M.A.Yee, D.A.Tang, Y.Christianson, D.W.

(2022) Biochemistry 61: 2014-2024

  • DOI: https://doi.org/10.1021/acs.biochem.2c00335
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The fungal species Aspergillus flavus produces an alkaloid terpenoid, flavunoidine, through a hybrid biosynthetic pathway combining both terpene cyclase and nonribosomal peptide synthetase enzymes. Flavunoidine consists of a tetracyclic, oxygenated sesquiterpene core decorated with dimethyl cadaverine and 5,5-dimethyl-l-pipecolate moieties. Unique to the flavunoidine biosynthetic pathway is FlvF, a putative enzyme implicated in stereospecific C-N bond formation as dimethyl cadaverine is linked to the sesquiterpene core to generate pre-flavunoidine. Here, we report the 2.6 Å resolution crystal structure of FlvF, which adopts the α-helical fold of a class I terpene synthase. However, FlvF is not a terpene synthase, as indicated by its lack of enzymatic activity with farnesyl diphosphate and its lack of signature metal ion binding motifs that would coordinate to catalytic Mg 2+ ions. Thus, FlvF is the first example of a protein that adopts a terpene synthase fold but is not a terpene synthase. Two Bis-Tris molecules bind in the active site of FlvF, and the binding of these ligands guided the docking of pre-flavunoidine to generate a model of the enzyme-product complex. Phylogenetic analysis of FlvF and related fungal homologues reveals conservation of residues that interact with the tetracyclic sesquiterpene in this model, but less conservation of residues interacting with the pendant amino moiety. This may hint toward the possibility that alternative amino substrates can be linked to a common sesquiterpene core by FlvF homologues to generate flavunoidine congeners, such as the phospholipase C inhibitor hispidospermidin.

  • Organizational Affiliation

    Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Terpene cyclase flvF
A, B, C, D, E
A, B, C, D, E, F, G, H
368Aspergillus flavus NRRL3357Mutation(s): 0 
Gene Names: flvFAFLA_135460
EC: 4.2.3
Find proteins for B8NHE1 (Aspergillus flavus (strain ATCC 200026 / FGSC A1120 / IAM 13836 / NRRL 3357 / JCM 12722 / SRRC 167))
Explore B8NHE1 
Go to UniProtKB:  B8NHE1
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupB8NHE1
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
BTB (Subject of Investigation/LOI)
Query on BTB

Download Ideal Coordinates CCD File 
I [auth A],
J [auth A],
L [auth B],
M [auth B],
P [auth D]
C8 H19 N O5
Query on GOL

Download Ideal Coordinates CCD File 
K [auth A]
N [auth B]
O [auth C]
Q [auth D]
R [auth E]
K [auth A],
N [auth B],
O [auth C],
Q [auth D],
R [auth E],
S [auth F],
T [auth G],
U [auth H]
C3 H8 O3
Experimental Data & Validation

Experimental Data

  • Resolution: 2.62 Å
  • R-Value Free: 0.243 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.209 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 90.65α = 90
b = 194.999β = 106.19
c = 101.37γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
Aimlessdata scaling
Cootmodel building

Structure Validation

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Ligand Structure Quality Assessment 

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesGM056838

Revision History  (Full details and data files)

  • Version 1.0: 2022-09-07
    Type: Initial release
  • Version 1.1: 2022-09-14
    Changes: Database references
  • Version 1.2: 2022-10-05
    Changes: Database references
  • Version 1.3: 2024-04-03
    Changes: Data collection, Refinement description