Crystal Structure of C101S Isocyanide Hydratase from Pseudomonas fluorescens

Experimental Data Snapshot

  • Resolution: 1.00 Å
  • R-Value Free: 0.146 
  • R-Value Work: 0.124 
  • R-Value Observed: 0.125 

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Evolution of New Enzymatic Function by Structural Modulation of Cysteine Reactivity in Pseudomonas fluorescens Isocyanide Hydratase.

Lakshminarasimhan, M.Madzelan, P.Nan, R.Milkovic, N.M.Wilson, M.A.

(2010) J Biol Chem 285: 29651-29661

  • DOI: https://doi.org/10.1074/jbc.M110.147934
  • Primary Citation of Related Structures:  
    3NON, 3NOO, 3NOQ, 3NOR, 3NOV

  • PubMed Abstract: 

    Isocyanide (formerly isonitrile) hydratase (EC is an enzyme of the DJ-1 superfamily that hydrates isocyanides to yield the corresponding N-formamide. In order to understand the structural basis for isocyanide hydratase (ICH) catalysis, we determined the crystal structures of wild-type and several site-directed mutants of Pseudomonas fluorescens ICH at resolutions ranging from 1.0 to 1.9 Å. We also developed a simple UV-visible spectrophotometric assay for ICH activity using 2-naphthyl isocyanide as a substrate. ICH contains a highly conserved cysteine residue (Cys(101)) that is required for catalysis and interacts with Asp(17), Thr(102), and an ordered water molecule in the active site. Asp(17) has carboxylic acid bond lengths that are consistent with protonation, and we propose that it activates the ordered water molecule to hydrate organic isocyanides. In contrast to Cys(101) and Asp(17), Thr(102) is tolerant of mutagenesis, and the T102V mutation results in a substrate-inhibited enzyme. Although ICH is similar to human DJ-1 (1.6 Å C-α root mean square deviation), structural differences in the vicinity of Cys(101) disfavor the facile oxidation of this residue that is functionally important in human DJ-1 but would be detrimental to ICH activity. The ICH active site region also exhibits surprising conformational plasticity and samples two distinct conformations in the crystal. ICH represents a previously uncharacterized clade of the DJ-1 superfamily that possesses a novel enzymatic activity, demonstrating that the DJ-1 core fold can evolve diverse functions by subtle modulation of the environment of a conserved, reactive cysteine residue.

  • Organizational Affiliation

    Department of Biochemistry and Redox Biology Center, University of Nebraska, Lincoln, Nebraska 68588-0664, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
ThiJ/PfpI family protein
A, B
231Pseudomonas fluorescensMutation(s): 1 
Gene Names: PFL_4109
Find proteins for Q4K977 (Pseudomonas fluorescens (strain ATCC BAA-477 / NRRL B-23932 / Pf-5))
Explore Q4K977 
Go to UniProtKB:  Q4K977
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ4K977
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.00 Å
  • R-Value Free: 0.146 
  • R-Value Work: 0.124 
  • R-Value Observed: 0.125 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 56.313α = 90
b = 56.403β = 112.42
c = 68.296γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
HKL-2000data reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-07-07
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2023-09-06
    Changes: Data collection, Database references, Derived calculations, Refinement description