4PTY

Crystal structure of the Escherichia coli alkanesulfonate FMN reductase SsuE in apo form


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.229 
  • R-Value Work: 0.179 
  • R-Value Observed: 0.182 

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Literature

Crystal Structure of Escherichia coli SsuE: Defining a General Catalytic Cycle for FMN Reductases of the Flavodoxin-like Superfamily.

Driggers, C.M.Dayal, P.V.Ellis, H.R.Karplus, P.A.

(2014) Biochemistry 53: 3509-3519

  • DOI: 10.1021/bi500314f
  • Primary Citation of Related Structures:  
    4PU0, 4PTY, 4PTZ

  • PubMed Abstract: 
  • The Escherichia coli sulfur starvation utilization (ssu) operon includes a two-component monooxygenase system consisting of a nicotinamide adenine dinucleotide phosphate (NADPH)-dependent flavin mononucleotide (FMN) reductase, SsuE, and a monooxygenase, SsuD ...

    The Escherichia coli sulfur starvation utilization (ssu) operon includes a two-component monooxygenase system consisting of a nicotinamide adenine dinucleotide phosphate (NADPH)-dependent flavin mononucleotide (FMN) reductase, SsuE, and a monooxygenase, SsuD. SsuE is part of the flavodoxin-like superfamily, and we report here the crystal structures of its apo, FMN-bound, and FMNH2-bound forms at ∼2 Å resolution. In the crystals, SsuE forms a tetramer that is a dimer of dimers similar to those seen for homologous FMN reductases, quinone reductases, and the WrbA family of enzymes. A π-helix present at the tetramer building interface is unique to the reductases from two-component monooxygenase systems. Analytical ultracentrifugation studies of SsuE confirm a dimer-tetramer equilibrium exists in solution, with FMN binding favoring the dimer. As the active site includes residues from both subunits, at least a dimeric association is required for the function of SsuE. The structures show that one FMN binds tightly in a deeply held site, which makes available a second binding site, in which either a second FMN or the nicotinamide of NADPH can bind. The FMNH2-bound structure shows subtle changes consistent with its binding being weaker than that of FMN. Combining this information with published kinetic studies, we propose a general catalytic cycle for two-component reductases of the flavodoxin-like superfamily, by which the enzyme can potentially provide FMNH2 to its partner monooxygenase by different routes depending on the FMN concentration and the presence of a partner monooxygenase.


    Organizational Affiliation

    Department of Biochemistry and Biophysics, Oregon State University , 2011 Agricultural and Life Sciences Building, Corvallis, Oregon 97331, United States.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
FMN reductase SsuEB [auth A], C [auth B], A [auth C], D191Escherichia coli K-12Mutation(s): 0 
Gene Names: ssuEycbPb0937JW0920
EC: 1.5.1.38
UniProt
Find proteins for P80644 (Escherichia coli (strain K12))
Explore P80644 
Go to UniProtKB:  P80644
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.229 
  • R-Value Work: 0.179 
  • R-Value Observed: 0.182 
  • Space Group: P 61 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 185.838α = 90
b = 185.838β = 90
c = 91.582γ = 120
Software Package:
Software NamePurpose
ADSCdata collection
PHASERphasing
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-06-18
    Type: Initial release