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Monothiol Glutaredoxins Function in Storing and Transporting [Fe2S2] Clusters Assembled on IscU Scaffold Proteins
- Source :
- Journal of the American Chemical Society
- Publication Year :
- 2012
- Publisher :
- American Chemical Society (ACS), 2012.
-
Abstract
- In the bacterial ISC system for iron-sulfur cluster assembly, IscU acts as a primary scaffold protein, and the molecular co-chaperones HscA and HscB specifically interact with IscU to facilitate ATP-driven cluster transfer. In this work, cluster transfer from Azotobacter vinelandii [Fe(2)S(2)](2+) cluster-bound IscU to apo-Grx5, a general purpose monothiol glutaredoxin in A. vinelandii, was monitored by circular dichroism spectroscopy, in the absence and in the presence of HscA/HscB/Mg-ATP. The results indicate a 700-fold enhancement in the rate of [Fe(2)S(2)](2+) cluster transfer in the presence of the co-chaperones and Mg-ATP, yielding a second-order rate constant of 20 000 M(-1) min(-1) at 23 °C. Thus, HscA and HscB are required for efficient ATP-dependent [Fe(2)S(2)](2+) cluster transfer from IscU to Grx5. The results support a role for monothiol Grx's in storing and transporting [Fe(2)S(2)](2+) clusters assembled on IscU and illustrate the limitations of interpreting in vitro cluster transfer studies involving [Fe(2)S(2)]-IscU in the absence of the dedicated HscA/HscB co-chaperone system.
- Subjects :
- Iron-Sulfur Proteins
Scaffold protein
Circular dichroism
010402 general chemistry
01 natural sciences
Biochemistry
Catalysis
03 medical and health sciences
Colloid and Surface Chemistry
Glutaredoxin
Cluster (physics)
Sulfhydryl Compounds
Glutaredoxins
030304 developmental biology
0303 health sciences
biology
Chemistry
Communication
Circular Dichroism
General Chemistry
biology.organism_classification
0104 chemical sciences
Crystallography
General purpose
Azotobacter vinelandii
Biophysics
biology.protein
Spectrophotometry, Ultraviolet
ISCU
Function (biology)
Subjects
Details
- ISSN :
- 15205126 and 00027863
- Volume :
- 134
- Database :
- OpenAIRE
- Journal :
- Journal of the American Chemical Society
- Accession number :
- edsair.doi.dedup.....806350b8962e91da46e136965af605a8