7C8N

Crystal structure of IscU H106A variant


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 0.197 
  • R-Value Work: 0.177 
  • R-Value Observed: 0.178 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

The Structure of the Dimeric State of IscU Harboring Two Adjacent [2Fe-2S] Clusters Provides Mechanistic Insights into Cluster Conversion to [4Fe-4S].

Kunichika, K.Nakamura, R.Fujishiro, T.Takahashi, Y.

(2021) Biochemistry 60: 1569-1572

  • DOI: https://doi.org/10.1021/acs.biochem.1c00112
  • Primary Citation of Related Structures:  
    7C8M, 7C8N

  • PubMed Abstract: 

    IscU serves as a scaffold for the de novo assembly of a [2Fe-2S] cluster prior to its delivery to recipient protein. It has also been proposed that on one dimer of bacterial IscU, two [2Fe-2S] clusters can be converted into a single [4Fe-4S] cluster. However, lack of structural information about the dimeric state of IscU has hindered our understanding of the underlying mechanisms. In this study, we determine the X-ray crystal structure of IscU from the thermophilic archaeon Methanothrix thermoacetophila and demonstrate a dimer structure of IscU in which two [2Fe-2S] clusters are facing each other in close proximity at the dimer interface. Our structure also reveals for the first time that Asp40 serves as a fourth ligand to the [2Fe-2S] cluster with three Cys ligands in each monomer, consistent with previous spectroscopic data. We confirm by EPR spectroscopic analysis that in solution two adjacent [2Fe-2S] clusters in the wild-type dimer are converted to a [4Fe-4S] cluster via reductive coupling. Furthermore, we find that the H106A substitution abolishes the reductive conversion to the [4Fe-4S] cluster without structural alteration, suggesting that His106 is functionally involved in this process. Overall, these findings provide a structural explanation for the assembly and conversion of Fe-S clusters on IscU and highlight a dynamic process that advances via association and dissociation of the IscU dimer.


  • Organizational Affiliation

    Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Shimo-okubo 255, Sakura-ku, Saitama 338-8570, Japan.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Nitrogen-fixing NifU domain protein137Methanothrix thermoacetophilaMutation(s): 1 
UniProt
Find proteins for A0B757 (Methanothrix thermoacetophila (strain DSM 6194 / JCM 14653 / NBRC 101360 / PT))
Explore A0B757 
Go to UniProtKB:  A0B757
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0B757
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
FES
Query on FES

Download Ideal Coordinates CCD File 
B [auth A]FE2/S2 (INORGANIC) CLUSTER
Fe2 S2
NIXDOXVAJZFRNF-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 0.197 
  • R-Value Work: 0.177 
  • R-Value Observed: 0.178 
  • Space Group: P 63 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 107.021α = 90
b = 107.021β = 90
c = 65.753γ = 120
Software Package:
Software NamePurpose
XSCALEdata scaling
REFMACrefinement
PDB_EXTRACTdata extraction
XDSdata reduction
MOLREPphasing

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Japan Society for the Promotion of Science (JSPS)Japan17K14510

Revision History  (Full details and data files)

  • Version 1.0: 2021-05-26
    Type: Initial release
  • Version 1.1: 2021-06-09
    Changes: Database references
  • Version 1.2: 2023-11-29
    Changes: Data collection, Database references, Refinement description