title: SufE transfers sulfur from SufS to SufB for iron-sulfur cluster assembly.
abstract: Iron-sulfur (Fe-S) clusters are key metal cofactors of metabolic, regulatory, and stress response proteins in most organisms. The unique properties of these clusters make them susceptible to disruption by iron starvation or oxidative stress. Both iron and sulfur can be perturbed under stress conditions, leading to Fe-S cluster defects. Bacteria and higher plants contain a specialized system for Fe-S cluster biosynthesis under stress, namely the Suf pathway. In Escherichia coli the Suf pathway consists of six proteins with functions that are only partially characterized. Here we describe how the SufS and SufE proteins interact with the SufBCD protein complex to facilitate sulfur liberation from cysteine and donation for Fe-S cluster assembly. It was previously shown that the cysteine desulfurase SufS donates sulfur to the sulfur transfer protein SufE. We have found here that SufE in turn interacts with the SufB protein for sulfur transfer to that protein. The interaction occurs only if SufC is present. Furthermore, SufB can act as a site for Fe-S cluster assembly in the Suf system. This provides the first evidence of a novel site for Fe-S cluster assembly in the SufBCD complex.
authors.affiliation: Laboratoire de Chimie et Biologie des Métaux, iRTSV/LCBM, Commissariat a l'Energie Atomique/CNRS/Universite Joseph Fourier, CEA-Grenoble, UMR 5249, 17 Avenue des Martyrs, 38054 Grenoble Cedex 09, France.
authors.forename: Gunhild
authors.initials: G
authors.lastname: Layer
authors.forename: S Aparna
authors.initials: SA
authors.lastname: Gaddam
authors.forename: Carla N
authors.initials: CN
authors.lastname: Ayala-Castro
authors.forename: Sandrine
authors.initials: S
authors.lastname: Ollagnier-de Choudens
authors.forename: David
authors.initials: D
authors.lastname: Lascoux
authors.forename: Marc
authors.initials: M
authors.lastname: Fontecave
authors.forename: F Wayne
authors.initials: FW
authors.lastname: Outten
mesh_terms: D001693:Biological Transport, Active / Q000502:physiology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D008190:Lyases / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology; D013455:Sulfur / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D046912:Multiprotein Complexes; C503794:Suf E protein, E coli; C498860:SufB protein, E coli; D013455:Sulfur; D007501:Iron; D008190:Lyases; C034278:selenocysteine lyase