title: The SufBCD Fe-S scaffold complex interacts with SufA for Fe-S cluster transfer.
abstract: Iron-sulfur clusters are key iron cofactors in biological pathways ranging from nitrogen fixation to respiration. Because of the toxicity of ferrous iron and sulfide to the cell, in vivo Fe-S cluster assembly transpires via multiprotein biosynthetic pathways. Fe-S cluster assembly proteins traffic iron and sulfide, assemble nascent Fe-S clusters, and correctly transfer Fe-S clusters to the appropriate target metalloproteins in vivo. The Gram-negative bacterium Escherichia coli contains a stress-responsive Fe-S cluster assembly system, the SufABCDSE pathway, that functions under iron starvation and oxidative stress conditions that compromise Fe-S homeostasis. Using a combination of protein-protein interaction and in vitro Fe-S cluster assembly assays, we have characterized the relative roles of the SufBCD complex and the SufA protein during Suf Fe-S cluster biosynthesis. These studies reveal that SufA interacts with SufBCD to accept Fe-S clusters formed de novo on the SufBCD complex. Our results represent the first biochemical evidence that the SufBCD complex within the Suf pathway functions as a novel Fe-S scaffold system to assemble nascent clusters and transfer them to the SufA Fe-S shuttle.
authors.affiliation: Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, South Carolina 29208, USA.
authors.forename: Harsimranjit K
authors.initials: HK
authors.lastname: Chahal
authors.forename: Yuyuan
authors.initials: Y
authors.lastname: Dai
authors.forename: Avneesh
authors.initials: A
authors.lastname: Saini
authors.forename: Carla
authors.initials: C
authors.lastname: Ayala-Castro
authors.forename: F Wayne
authors.initials: FW
authors.lastname: Outten
mesh_terms: D001483:Base Sequence; D002942:Circular Dichroism; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D006706:Homeostasis; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D017931:DNA Primers; D029968:Escherichia coli Proteins; D007506:Iron-Sulfur Proteins