Cysteine desulfurases abstract sulfur from the substrate cysteine, generate a covalent persulfide on the active site cysteine of the enzyme, and then donate the persulfide sulfur to various recipients such as Fe–S clusters. In Saccharomyces cerevisiae, the Nfs1p protein is the only known cysteine desulfurase, and it forms a complex with Isd11p (Nfs1p·Isd11p). Both of these proteins are found primarily in mitochondria and both are essential for cell viability. In the present study we show, using the results of experiments with isolated mitochondria and purified proteins, that Isd11p is required for the cysteine desulfurase activity of Nfs1p. Whereas Nfs1p by itself was inactive, the Nfs1p·Isd11p complex formed persulfide and was active as a cysteine desulfurase. In the absence of Isd11p, Nfs1p was able to bind the substrate cysteine but failed to form a persulfide. Addition of Isd11p allowed Nfs1p with bound substrate to generate a covalent persulfide. We suggest that Isd11p induces an activating conformational change in Nfs1p to bring the bound substrate and the active site cysteine in proximity for persulfide formation. Thus mitochondrial Nfs1p is different from bacterial cysteine desulfurases that are active in the absence of accessory proteins. Isd11p may serve to regulate cysteine desulfurase activity in mitochondria.
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December 2012
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Research Article|
November 07 2012
Persulfide formation on mitochondrial cysteine desulfurase: enzyme activation by a eukaryote-specific interacting protein and Fe–S cluster synthesis
Alok Pandey;
Alok Pandey
*Department of Pharmacology and Physiology, University of Medicine and Dentistry, New Jersey Medical School, Newark, NJ 07101, U.S.A.
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Ramesh Golla;
Ramesh Golla
†Department of Medicine, Division of Hematology-Oncology, University of Pennsylvania, Philadelphia, PA 19104, U.S.A.
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Heeyong Yoon;
Heeyong Yoon
†Department of Medicine, Division of Hematology-Oncology, University of Pennsylvania, Philadelphia, PA 19104, U.S.A.
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Andrew Dancis;
Andrew Dancis
†Department of Medicine, Division of Hematology-Oncology, University of Pennsylvania, Philadelphia, PA 19104, U.S.A.
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Debkumar Pain
Debkumar Pain
1
*Department of Pharmacology and Physiology, University of Medicine and Dentistry, New Jersey Medical School, Newark, NJ 07101, U.S.A.
1To whom correspondence should be addressed (email painde@umdnj.edu).
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Biochem J (2012) 448 (2): 171–187.
Article history
Received:
June 11 2012
Revision Received:
August 24 2012
Accepted:
August 28 2012
Accepted Manuscript online:
August 28 2012
Citation
Alok Pandey, Ramesh Golla, Heeyong Yoon, Andrew Dancis, Debkumar Pain; Persulfide formation on mitochondrial cysteine desulfurase: enzyme activation by a eukaryote-specific interacting protein and Fe–S cluster synthesis. Biochem J 1 December 2012; 448 (2): 171–187. doi: https://doi.org/10.1042/BJ20120951
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