9MC1 | pdb_00009mc1

Trans-acting enoylreductase PhiaB involved in the phialotideA biosynthesis pathway

• PDB DOI: https://doi.org/10.2210/pdb9MC1/pdb

• Classification: OXIDOREDUCTASE
• Organism(s): Pseudophialophora
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2025-03-17 Released: 2025-04-16 
• Deposition Author(s): Takekawa, Y., Takino, J., Sato, S., Yabuno, N., Oikawa, H., Ose, T., Minami, A.
• Funding Organization(s): Japan Society for the Promotion of Science (JSPS)

---

Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.90 Å
• R-Value Free: 
  0.273 (Depositor), 0.274 (DCC) 
• R-Value Work: 
  0.226 (Depositor), 0.227 (DCC) 
• R-Value Observed: 
  0.228 (Depositor) 

Starting Model: in silico

Literature

Chain-length preference of trans-acting enoylreductases involved in the biosynthesis of fungal polyhydroxy polyketides.

Takekawa, Y., Takino, J., Sato, S., Oikawa, H., Ose, T., Minami, A.

(2025) Biochem Biophys Res Commun 761: 151737-151737

• PubMed: 40186921 
• DOI: https://doi.org/10.1016/j.bbrc.2025.151737
• Primary Citation of Related Structures:  
  9MC1


• PubMed Abstract: 
  

  Fungal polyketides are diverse natural products synthesized by iterative polyketide synthases (i-PKSs) and modified by enzymes such as trans-acting enoylreductases (trans-ERs). In this study, we investigated PhiaB and PhomB, trans-ERs involved in the biosynthesis of polyhydroxy polyketides, phialotides, and phomenoic acids. In vitro assays using substrate analogs revealed distinct chain-length preferences. X-ray structural analysis of PhiaB revealed distinct N-terminal, central, and C-terminal regions. The importance of the central region, which possesses a canonical Rossmann fold for cofactor recognition, was further supported by biosynthetic refactoring using a chimeric enzyme. Docking studies revealed key amino acid residues that may be involved in substrate/cofactor recognition. These findings advance our understanding of trans-ER function, providing opportunities for the synthesis of structurally different polyhydroxy polyketides by genetic engineering of polyhydroxy polyketide biosynthesis.

---

Organizational Affiliation: 
• Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810, Japan.
Division of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan.
Department of Chemistry, Institute of Science Tokyo, Tokyo, 152-8551, Japan.
Division of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan. Electronic address: [e-mail].
Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810, Japan. Electronic address: [e-mail].
Department of Chemistry, Institute of Science Tokyo, Tokyo, 152-8551, Japan. Electronic address: [e-mail].

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Macromolecule Content 

• Total Structure Weight: 40.08 kDa 
• Atom Count: 2,645 
• Modeled Residue Count: 354 
• Deposited Residue Count: 375 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Trans-acting enoylreductase	A	375	Pseudophialophora	Mutation(s): 0

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.90 Å
• R-Value Free:  0.273 (Depositor), 0.274 (DCC) 
• R-Value Work:  0.226 (Depositor), 0.227 (DCC) 
• R-Value Observed: 0.228 (Depositor) 

Space Group: H 3 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 185.97	α = 90
b = 185.97	β = 90
c = 58.877	γ = 120

Software Package:

Software Name	Purpose
XDS	data reduction
XDS	data scaling
PHENIX	phasing
Coot	model building
PHENIX	refinement

Structure Validation

Entry History & Funding Information

Deposition Data

• Released Date: 2025-04-16 
Deposition Author(s): Takekawa, Y., Takino, J., Sato, S., Yabuno, N., Oikawa, H., Ose, T., Minami, A.

---

Funding Organization	Location	Grant Number
Japan Society for the Promotion of Science (JSPS)	Japan	JP23H04533

Revision History  

• Version 1.0: 2025-04-16
  Type: Initial release