Characterization Of Yeast Cysteine Desulfurase Complex And Its Role In Fe-S Cluster Assembly

Anjali Patel, Wayne State University


The chemical and electronic variability of Fe-S clusters are surely key factors for why these cofactors are so prevalent in biology since they can serve as reaction centers in several functionally diverse metalloproteins. Due to their reactive properties, it is not surprising that Fe-S cluster biogenesis is carefully controlled by a dedicated set of proteins that work in a regulated but orchestrated manner to drive cofactor production. During Fe-S cluster biosynthesis, cysteine desulfurase functions as the sulfur source for assembling the cofactors and this enzyme operates by producing sulfane sulfur from L-cysteine and providing the sulfur in its activated form to the assembly scaffold protein via transfer of a persulfide intermediate to drive cluster assembly. In yeast, the cysteine desulfurase “Nfs1” is supported by the accessory protein “Isd11”. Although several functional studies support the physiological dependence of Nfs1 for being active only with Isd11, less attention has been given to investigate the molecular properties of each protein alone and in a complex and also in elucidating the biophysical basis of their coordinated activity. Combined with previously published results from other labs, our molecular characterization enhances the understanding of the activity of the Nfs1-Isd11 complex partners in working together to drive mitochondrial Fe-S cluster biogenesis. Recent studies have shown that ACP is a stable binding partner for the mitochondrial cysteine desulfurase and this interaction suggests a possible link between fatty acid synthesis and Fe-S cluster biogenesis. This chapter describes an initial work on the Yeast ortholog “Acp1”. The objective of this study is to characterize the interaction of Acp1 with Nfs1-Isd11, Fe-S cluster assembly, and iron itself.