3MMA

Dissimilatory sulfite reductase phosphate complex


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.192 
  • R-Value Observed: 0.195 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 2.0 of the entry. See complete history


Literature

Reaction cycle of the dissimilatory sulfite reductase from Archaeoglobus fulgidus.

Parey, K.Warkentin, E.Kroneck, P.M.Ermler, U.

(2010) Biochemistry 49: 8912-8921

  • DOI: https://doi.org/10.1021/bi100781f
  • Primary Citation of Related Structures:  
    3MM5, 3MM6, 3MM7, 3MM8, 3MM9, 3MMA, 3MMB

  • PubMed Abstract: 

    A vital process in the biogeochemical sulfur cycle is the dissimilatory sulfate reduction pathway in which sulfate (SO₄⁻²) is converted to hydrogen sulfide (H₂S). Dissimilatory sulfite reductase (dSir), its key enzyme, hosts a unique siroheme-[4Fe-4S] cofactor and catalyzes the six-electron reduction of sulfite (SO₃²⁻) to H₂S. To explore this reaction, we determined the X-ray structures of dSir from the archaeon Archaeoglobus fulgidus in complex with sulfite, sulfide (S²⁻) carbon monoxide (CO), cyanide (CN⁻), nitrite (NO₂⁻), nitrate (NO₃⁻), and phosphate (PO₄³⁻). Activity measurements indicated that dSir of A. fulgidus reduces, besides sulfite and nitrite, thiosulfate (S₂O₃²⁻) and trithionate (S₃O₆²⁻) and produces the latter two compounds besides sulfide. On this basis, a three-step mechanism was proposed, each step consisting of a two-electron transfer, a two-proton uptake, and a dehydration event. In comparison, the related active site structures of the assimilatory sulfite reductase (aSir)- and dSir-SO₃²⁻complexes reveal different conformations of Argα170 and Lysα211 both interacting with the sulfite oxygens (its sulfur atom coordinates the siroheme iron), a sulfite rotation of ~60° relative to each other, and different access of solvent molecules to the sulfite oxygens from the active site cleft. Therefore, solely in dSir a further sulfite molecule can be placed in van der Waals contact with the siroheme-ligated sulfite or sulfur-oxygen intermediates necessary for forming thiosulfate and trithionate. Although reported for dSir from several sulfate-reducing bacteria, the in vivo relevance of their formation is questionable.


  • Organizational Affiliation

    Max-Planck-Institut für Biophysik, Max-von-Laue-Strasse 3, Frankfurt, Germany.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Sulfite reductase, dissimilatory-type subunit alphaA,
C [auth D]
418Archaeoglobus fulgidusMutation(s): 0 
EC: 1.8.99.3 (PDB Primary Data), 1.8.1.22 (UniProt)
UniProt
Find proteins for Q59109 (Archaeoglobus fulgidus (strain ATCC 49558 / DSM 4304 / JCM 9628 / NBRC 100126 / VC-16))
Explore Q59109 
Go to UniProtKB:  Q59109
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ59109
Sequence Annotations
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Sulfite reductase, dissimilatory-type subunit betaB,
D [auth E]
366Archaeoglobus fulgidusMutation(s): 0 
EC: 1.8.99.3 (PDB Primary Data), 1.8.1.22 (UniProt)
UniProt
Find proteins for Q59110 (Archaeoglobus fulgidus (strain ATCC 49558 / DSM 4304 / JCM 9628 / NBRC 100126 / VC-16))
Explore Q59110 
Go to UniProtKB:  Q59110
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ59110
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
SRM
Query on SRM

Download Ideal Coordinates CCD File 
E [auth A],
K [auth B],
L [auth D],
Q [auth E]
SIROHEME
C42 H44 Fe N4 O16
DLKSSIHHLYNIKN-MWBYXLBFSA-L
SF4
Query on SF4

Download Ideal Coordinates CCD File 
F [auth A]
G [auth A]
I [auth B]
J [auth B]
M [auth D]
F [auth A],
G [auth A],
I [auth B],
J [auth B],
M [auth D],
N [auth D],
O [auth E],
P [auth E]
IRON/SULFUR CLUSTER
Fe4 S4
LJBDFODJNLIPKO-UHFFFAOYSA-N
PO4
Query on PO4

Download Ideal Coordinates CCD File 
H [auth A]PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.192 
  • R-Value Observed: 0.195 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 94.6α = 90
b = 68.9β = 107.5
c = 145.1γ = 90
Software Package:
Software NamePurpose
MAR345data collection
REFMACrefinement
XDSdata reduction
XDSdata scaling
REFMACphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-07-21
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Refinement description, Version format compliance
  • Version 1.2: 2017-11-08
    Changes: Refinement description
  • Version 1.3: 2023-09-06
    Changes: Data collection, Database references, Derived calculations, Refinement description
  • Version 2.0: 2023-12-27
    Changes: Data collection, Non-polymer description, Structure summary