MoeE5 in complex with UDP-glucose and NAD

Experimental Data Snapshot

  • Resolution: 1.66 Å
  • R-Value Free: 0.191 
  • R-Value Work: 0.155 
  • R-Value Observed: 0.157 

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Structure of an antibiotic-synthesizing UDP-glucuronate 4-epimerase MoeE5 in complex with substrate.

Sun, H.Ko, T.P.Liu, W.Liu, W.Zheng, Y.Chen, C.C.Guo, R.T.

(2020) Biochem Biophys Res Commun 521: 31-36

  • DOI: https://doi.org/10.1016/j.bbrc.2019.10.035
  • Primary Citation of Related Structures:  
    6KV9, 6KVC

  • PubMed Abstract: 

    The epimerase MoeE5 from Streptomyces viridosporus converts UDP-glucuronic acid (UDP-GlcA) to UDP-galacturonic acid (UDP-GalA) to provide the first sugar in synthesizing moenomycin, a potent inhibitor against bacterial peptidoglycan glycosyltransferases. The enzyme belongs to the UDP-hexose 4-epimerase family, and uses NAD + as its cofactor. Here we present the complex crystal structures of MoeE5/NAD + /UDP-GlcA and MoeE5/NAD + /UDP-glucose, determined at 1.48 Å and 1.66 Å resolution. The cofactor NAD + is bound to the N-terminal Rossmann-fold domain and the substrate is bound to the smaller C-terminal domain. In both crystals the C4 atom of the sugar moiety of the substrate is in close proximity to the C4 atom of the nicotinamide of NAD + , and the O4 atom of the sugar is also hydrogen bonded to the side chain of Tyr154, suggesting a productive binding mode. As the first complex structure of this protein family with a bound UDP-GlcA in the active site, it shows an extensive hydrogen-bond network between the enzyme and the substrate. We further built a model with the product UDP-GalA, and found that the unique Arg192 of MoeE5 might play an important role in the catalytic pathway. Consequently, MoeE5 is likely a specific epimerase for UDP-GlcA to UDP-GalA conversion, rather than a promiscuous enzyme as some other family members.

  • Organizational Affiliation

    Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
MoeE5346Streptomyces viridosporus ATCC 14672Mutation(s): 0 
Gene Names: moeE5
Find proteins for A0A003 (Streptomyces viridosporus)
Explore A0A003 
Go to UniProtKB:  A0A003
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A003
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
NAD (Subject of Investigation/LOI)
Query on NAD

Download Ideal Coordinates CCD File 
C21 H27 N7 O14 P2
UPG (Subject of Investigation/LOI)
Query on UPG

Download Ideal Coordinates CCD File 
C15 H24 N2 O17 P2
Experimental Data & Validation

Experimental Data

  • Resolution: 1.66 Å
  • R-Value Free: 0.191 
  • R-Value Work: 0.155 
  • R-Value Observed: 0.157 
  • Space Group: P 41 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 59.047α = 90
b = 59.047β = 90
c = 197.975γ = 90
Software Package:
Software NamePurpose
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2019-11-13
    Type: Initial release
  • Version 1.1: 2020-01-08
    Changes: Database references
  • Version 1.2: 2023-11-22
    Changes: Data collection, Database references, Refinement description