H47Q NicC with bound FAD

Experimental Data Snapshot

  • Resolution: 1.51 Å
  • R-Value Free: 0.211 
  • R-Value Work: 0.176 
  • R-Value Observed: 0.178 

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Ligand bound structure of a 6-hydroxynicotinic acid 3-monooxygenase provides mechanistic insights.

Turlington, Z.R.Vaz Ferreira de Macedo, S.Perry, K.Belsky, S.L.Faust, J.A.Snider, M.J.Hicks, K.A.

(2024) Arch Biochem Biophys 752: 109859-109859

  • DOI: https://doi.org/10.1016/j.abb.2023.109859
  • Primary Citation of Related Structures:  
    8UIQ, 8UIV

  • PubMed Abstract: 

    6-Hydroxynicotinic acid 3-monooxygenase (NicC) is a bacterial enzyme involved in the degradation of nicotinic acid. This enzyme is a Class A flavin-dependent monooxygenase that catalyzes a unique decarboxylative hydroxylation. The unliganded structure of this enzyme has previously been reported and studied using steady- and transient-state kinetics to support a comprehensive kinetic mechanism. Here we report the crystal structure of the H47Q NicC variant in both a ligand-bound (solved to 2.17 Å resolution) and unliganded (1.51 Å resolution) form. Interestingly, in the liganded form, H47Q NicC is bound to 2-mercaptopyridine (2-MP), a contaminant present in the commercial stock of 6-mercaptopyridine-3-carboxylic acid(6-MNA), a substrate analogue. 2-MP binds weakly to H47Q NicC and is not a substrate for the enzyme. Based on kinetic and thermodynamic characterization, we have fortuitously captured a catalytically inactive H47Q NicC•2-MP complex in our crystal structure. This complex reveals interesting mechanistic details about the reaction catalyzed by 6-hydroxynicotinic acid 3-monooxygenase.

  • Organizational Affiliation

    Department of Chemistry, State University of New York at Cortland, Cortland, NY, 13045, United States.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
6-hydroxynicotinate 3-monooxygenase405Pseudomonas putida KT2440Mutation(s): 1 
Gene Names: nicC
Find proteins for Q88FY2 (Pseudomonas putida (strain ATCC 47054 / DSM 6125 / CFBP 8728 / NCIMB 11950 / KT2440))
Explore Q88FY2 
Go to UniProtKB:  Q88FY2
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ88FY2
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
FAD (Subject of Investigation/LOI)
Query on FAD

Download Ideal Coordinates CCD File 
C27 H33 N9 O15 P2
Experimental Data & Validation

Experimental Data

  • Resolution: 1.51 Å
  • R-Value Free: 0.211 
  • R-Value Work: 0.176 
  • R-Value Observed: 0.178 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 47.468α = 90
b = 69.735β = 90
c = 115.639γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
XDSdata scaling

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Science Foundation (NSF, United States)United States1817633

Revision History  (Full details and data files)

  • Version 1.0: 2024-02-21
    Type: Initial release