title: Persulfide formation on mitochondrial cysteine desulfurase: enzyme activation by a eukaryote-specific interacting protein and Fe-S cluster synthesis.
abstract: 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.
authors.affiliation: Department of Pharmacology and Physiology, University of Medicine and Dentistry, New Jersey Medical School, Newark, NJ 07101, USA.
authors.forename: Alok
authors.initials: A
authors.lastname: Pandey
authors.forename: Ramesh
authors.initials: R
authors.lastname: Golla
authors.forename: Heeyong
authors.initials: H
authors.lastname: Yoon
authors.forename: Andrew
authors.initials: A
authors.lastname: Dancis
authors.forename: Debkumar
authors.initials: D
authors.lastname: Pain
mesh_terms: D000483:Alleles; D013437:Carbon-Sulfur Lyases / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D005800:Genes, Fungal; D007506:Iron-Sulfur Proteins / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D013440:Sulfides / Q000378:metabolism*; D013466:Sulfurtransferases / Q000235:genetics / Q000378:metabolism*
chemical_list: D007506:Iron-Sulfur Proteins; C508374:Isd11 protein, S cerevisiae; D024101:Mitochondrial Proteins; D009097:Multienzyme Complexes; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D013440:Sulfides; C051552:persulfides; D013466:Sulfurtransferases; C115912:NFS1 protein, S cerevisiae; D013437:Carbon-Sulfur Lyases; C080546:cysteine desulfurase