1DDG

CRYSTAL STRUCTURE OF SIR-FP60


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.01 Å
  • R-Value Free: 0.289 

wwPDB Validation 3D Report Full Report


This is version 1.4 of the entry. See complete history

Literature

Four crystal structures of the 60 kDa flavoprotein monomer of the sulfite reductase indicate a disordered flavodoxin-like module.

Gruez, A.Pignol, D.Zeghouf, M.Coves, J.Fontecave, M.Ferrer, J.L.Fontecilla-Camps, J.C.

(2000) J.Mol.Biol. 299: 199-212

  • DOI: 10.1006/jmbi.2000.3748
  • Primary Citation of Related Structures:  1DDI

  • PubMed Abstract: 
  • Escherichia coli NADPH-sulfite reductase (SiR) is a 780 kDa multimeric hemoflavoprotein composed of eight alpha-subunits (SiR-FP) and four beta-subunits (SiR-HP) that catalyses the six electron reduction of sulfite to sulfide. Each beta-subunit conta ...

    Escherichia coli NADPH-sulfite reductase (SiR) is a 780 kDa multimeric hemoflavoprotein composed of eight alpha-subunits (SiR-FP) and four beta-subunits (SiR-HP) that catalyses the six electron reduction of sulfite to sulfide. Each beta-subunit contains a Fe4S4 cluster and a siroheme, and each alpha-subunit binds one FAD and one FMN as prosthetic groups. The FAD gets electrons from NADPH, and the FMN transfers the electrons to the metal centers of the beta-subunit for sulfite reduction. We report here the 1.94 A X-ray structure of SiR-FP60, a recombinant monomeric fragment of SiR-FP that binds both FAD and FMN and retains the catalytic properties of the native protein. The structure can be divided into three domains. The carboxy-terminal part of the enzyme is composed of an antiparallel beta-barrel which binds the FAD, and a variant of the classical pyridine dinucleotide binding fold which binds NADPH. These two domains form the canonic FNR-like module, typical of the ferredoxin NADP+ reductase family. By analogy with the structure of the cytochrome P450 reductase, the third domain, composed of seven alpha-helices, is supposed to connect the FNR-like module to the N-terminal flavodoxine-like module. In four different crystal forms, the FMN-binding module is absent from electron density maps, although mass spectroscopy, amino acid sequencing and activity experiments carried out on dissolved crystals indicate that a functional module is present in the protein. Our results clearly indicate that the interaction between the FNR-like and the FMN-like modules displays lower affinity than in the case of cytochrome P450 reductase. The flexibility of the FMN-binding domain may be related, as observed in the case of cytochrome bc1, to a domain reorganisation in the course of electron transfer. Thus, a movement of the FMN-binding domain relative to the rest of the enzyme may be a requirement for its optimal positioning relative to both the FNR-like module and the beta-subunit.


    Organizational Affiliation

    Laboratoire de Cristallographie et Cristallogenèse des Protéines Institut de Biologie Structurale J.P. Ebel, CEA-CNRS, Grenoble, France.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
SULFITE REDUCTASE (NADPH) FLAVOPROTEIN ALPHA-COMPONENT
A, B
374Escherichia coli (strain K12)Gene Names: cysJ
EC: 1.8.1.2
Find proteins for P38038 (Escherichia coli (strain K12))
Go to UniProtKB:  P38038
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
B
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
FAD
Query on FAD

Download SDF File 
Download CCD File 
A, B
FLAVIN-ADENINE DINUCLEOTIDE
C27 H33 N9 O15 P2
VWWQXMAJTJZDQX-UYBVJOGSSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.01 Å
  • R-Value Free: 0.289 
  • Space Group: P 1
Unit Cell:
Length (Å)Angle (°)
a = 34.840α = 79.71
b = 82.540β = 83.05
c = 105.360γ = 89.90
Software Package:
Software NamePurpose
ARP/wARPmodel building
SHELXmodel building
REFMACrefinement
SHELXL-97refinement
SHELXphasing
ARPmodel building
AMoREphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2000-11-13
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-10-04
    Type: Refinement description
  • Version 1.4: 2018-01-31
    Type: Experimental preparation