2L4X

Solution Structure of apo-IscU(WT)


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the least restraint violations 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Three-Dimensional Structure and Determinants of Stability of the Iron-Sulfur Cluster Scaffold Protein IscU from Escherichia coli.

Kim, J.H.Tonelli, M.Kim, T.Markley, J.L.

(2012) Biochemistry 51: 5557-5563

  • DOI: 10.1021/bi300579p
  • Primary Citation of Related Structures:  2KQK

  • PubMed Abstract: 
  • The highly conserved protein, IscU, serves as the scaffold for iron-sulfur cluster (ISC) assembly in the ISC system common to bacteria and eukaryotic mitochondria. The apo-form of IscU from Escherichia coli has been shown to populate two slowly inter ...

    The highly conserved protein, IscU, serves as the scaffold for iron-sulfur cluster (ISC) assembly in the ISC system common to bacteria and eukaryotic mitochondria. The apo-form of IscU from Escherichia coli has been shown to populate two slowly interconverting conformational states: one structured (S) and one dynamically disordered (D). Furthermore, single-site amino acid substitutions have been shown to shift the equilibrium between the metamorphic states. Here, we report three-dimensional structural models derived from NMR spectroscopy for the S-state of wild-type (WT) apo-IscU, determined under conditions where the protein was 80% in the S-state and 20% in the D-state, and for the S-state of apo-IscU(D39A), determined under conditions where the protein was ~95% in the S-state. We have used these structures in interpreting the effects of single site amino acid substitutions that alter %S = (100 × [S])/([S] + [D]). These include different residues at the same site, %S: D39V > D39L > D39A > D39G ≈ WT, and alanine substitutions at different sites, %S: N90A > S107A ≈ E111A > WT. Hydrophobic residues at residue 39 appear to stabilize the S-state by decreasing the flexibility of the loops that contain the conserved cysteine residues. The alanine substitutions at positions 90, 107, and 111, on the other hand, stabilize the protein without affecting the loop dynamics. In general, the stability of the S-state correlates with the compactness and thermal stability of the variant.


    Organizational Affiliation

    Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Iron-sulfur cluster assembly scaffold protein
A
128Escherichia coli (strain K12)Gene Names: iscU (nifU, yfhN)
Find proteins for P0ACD4 (Escherichia coli (strain K12))
Go to UniProtKB:  P0ACD4
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the least restraint violations 
  • Olderado: 2L4X Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2011-12-07
    Type: Initial release
  • Version 1.1: 2012-07-11
    Type: Database references
  • Version 1.2: 2012-09-26
    Type: Database references