title: The role of CyaY in iron sulfur cluster assembly on the E. coli IscU scaffold protein.
abstract: Progress in understanding the mechanism underlying the enzymatic formation of iron-sulfur clusters is difficult since it involves a complex reaction and a multi-component system. By exploiting different spectroscopies, we characterize the effect on the enzymatic kinetics of cluster formation of CyaY, the bacterial ortholog of frataxin, on cluster formation on the scaffold protein IscU. Frataxin/CyaY is a highly conserved protein implicated in an incurable ataxia in humans. Previous studies had suggested a role of CyaY as an inhibitor of iron sulfur cluster formation. Similar studies on the eukaryotic proteins have however suggested for frataxin a role as an activator. Our studies independently confirm that CyaY slows down the reaction and shed new light onto the mechanism by which CyaY works. We observe that the presence of CyaY does not alter the relative ratio between [2Fe2S](2+) and [4Fe4S](2+) but directly affects enzymatic activity.
authors.affiliation: Medical Research Council National Institute for Medical Research, London, United Kingdom.
authors.forename: Clara
authors.initials: C
authors.lastname: Iannuzzi
authors.forename: Salvatore
authors.initials: S
authors.lastname: Adinolfi
authors.forename: Barry D
authors.initials: BD
authors.lastname: Howes
authors.forename: Ricardo
authors.initials: R
authors.lastname: Garcia-Serres
authors.forename: Martin
authors.initials: M
authors.lastname: Clémancey
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Latour
authors.forename: Giulietta
authors.initials: G
authors.lastname: Smulevich
authors.forename: Annalisa
authors.initials: A
authors.lastname: Pastore
mesh_terms: D000042:Absorption; D004926:Escherichia coli / Q000201:enzymology / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000378:metabolism*; D015204:Spectroscopy, Mossbauer; D013059:Spectrum Analysis, Raman; D013455:Sulfur / Q000378:metabolism*
chemical_list: C120906:CyaY protein, E coli; D029968:Escherichia coli Proteins; D007506:Iron-Sulfur Proteins; C411665:IscU protein, E coli; D013455:Sulfur; D007501:Iron