8D7F

FlvF from Aspergillus flavus in complex with Bis-Tris

Summary for 8D7F

• Entry DOI: 10.2210/pdb8d7f/pdb
• Descriptor: Terpene cyclase flvF, 2-[BIS-(2-HYDROXY-ETHYL)-AMINO]-2-HYDROXYMETHYL-PROPANE-1,3-DIOL, GLYCEROL (3 entities in total)
• Functional Keywords: fungal protein, terpene cyclase fold, c-n bond formation, lyase
• Biological source: Aspergillus flavus (strain ATCC 200026 / FGSC A1120 / IAM 13836 / NRRL 3357 / JCM 12722 / SRRC 167)
• Total number of polymer chains: 8
• Total formula weight: 342088.14

Authors

Tararina, M.A.,Christianson, D.W. (deposition date: 2022-06-07, release date: 2022-09-07, Last modification date: 2024-04-03)

Primary citation

Tararina, M.A.,Yee, D.A.,Tang, Y.,Christianson, D.W.
Structure of the Repurposed Fungal Terpene Cyclase FlvF Implicated in the C-N Bond-Forming Reaction of Flavunoidine Biosynthesis.
Biochemistry, 61:2014-2024, 2022

PubMed Abstract: The fungal species 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 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.

PubMed: 36037799
DOI: 10.1021/acs.biochem.2c00335

Experimental method

X-RAY DIFFRACTION (2.62 Å)