title: Characterization of Arabidopsis thaliana SufE2 and SufE3: functions in chloroplast iron-sulfur cluster assembly and Nad synthesis.
abstract: In this study we characterize two novel chloroplast SufE-like proteins from Arabidopsis thaliana. Other SufE-like proteins, including the previously described A. thaliana CpSufE, participate in sulfur mobilization for Fe-S biosynthesis through activation of cysteine desulfurization by NifS-like proteins. In addition to CpSufE, the Arabidopsis genome encodes two other proteins with SufE domains, SufE2 and SufE3. SufE2 has plastid targeting information. Purified recombinant SufE2 could activate the cysteine desulfurase activity of CpNifS 40-fold. SufE2 expression was flower-specific and high in pollen; we therefore hypothesize that SufE2 has a specific function in pollen Fe-S cluster biosynthesis. SufE3, also a plastid targeted protein, was expressed at low levels in all major plant organs. The mature SufE3 contains two domains, one SufE-like and one with similarity to the bacterial quinolinate synthase, NadA. Indeed SufE3 displayed both SufE activity (stimulating CpNifS cysteine desulfurase activity 70-fold) and quinolinate synthase activity. The full-length protein was shown to carry a highly oxygen-sensitive (4Fe-4S) cluster at its NadA domain, which could be reconstituted by its own SufE domain in the presence of CpNifS, cysteine and ferrous iron. Knock-out of SufE3 in Arabidopsis is embryolethal. We conclude that SufE3 is the NadA enzyme of A. thaliana, involved in a critical step during NAD biosynthesis.
authors: Biology Department and Program in Molecular Plant Biology, Colorado State University, Fort Collins, Colorado 80523.
authors: Narayana Murthy U
authors: NMU
authors: M
authors: Laboratoire de Chimie et Biologie des Métaux, UMR UJF/CEA/CNRS no. 5249, Institut de Recherche en Technologie et Sciences pour le Vivant/Laboratoire de Chimie et Biologie des Métauk, CEA Grenoble, 17 Avenue des Martyrs, 38054 Grenoble, Cedex 09, France.
authors: Sandrine
authors: S
authors: Ollagnier-de-Choudens
authors: NCSR, Demokritos, Institute of Materials Science, 15310 Ag. Paraskevi, Attiki, Greece.
authors: Yiannis
authors: Y
authors: Sanakis
authors: Biology Department and Program in Molecular Plant Biology, Colorado State University, Fort Collins, Colorado 80523.
authors: Salah E
authors: SE
authors: Abdel-Ghany
authors: Laboratoire de Chimie et Biologie des Métaux, UMR UJF/CEA/CNRS no. 5249, Institut de Recherche en Technologie et Sciences pour le Vivant/Laboratoire de Chimie et Biologie des Métauk, CEA Grenoble, 17 Avenue des Martyrs, 38054 Grenoble, Cedex 09, France.
authors: Carine
authors: C
authors: Rousset
authors: Biology Department and Program in Molecular Plant Biology, Colorado State University, Fort Collins, Colorado 80523.
authors: Hong
authors: H
authors: Ye
authors: Laboratoire de Chimie et Biologie des Métaux, UMR UJF/CEA/CNRS no. 5249, Institut de Recherche en Technologie et Sciences pour le Vivant/Laboratoire de Chimie et Biologie des Métauk, CEA Grenoble, 17 Avenue des Martyrs, 38054 Grenoble, Cedex 09, France.
authors: Marc
authors: M
authors: Fontecave
authors: Biology Department and Program in Molecular Plant Biology, Colorado State University, Fort Collins, Colorado 80523.
authors: Elizabeth A H
authors: EAH
authors: Pilon-Smits
authors: Biology Department and Program in Molecular Plant Biology, Colorado State University, Fort Collins, Colorado 80523. Electronic address: pilon@lamar.colostate.edu.
authors: Marinus
authors: M
authors: Pilon
mesh_terms: D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism / Q000502:physiology*; D013437:Carbon-Sulfur Lyases / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D004926:Escherichia coli / Q000378:metabolism; D005816:Genetic Complementation Test; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D009841:Oligonucleotides / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D018087:Plastids / Q000378:metabolism; D011058:Pollen / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary
chemical_list: D029681:Arabidopsis Proteins; C509435:At4g26500 protein, Arabidopsis; D004269:DNA, Bacterial; D007506:Iron-Sulfur Proteins; D009841:Oligonucleotides; C036483:T-DNA; D013437:Carbon-Sulfur Lyases; C080546:cysteine desulfurase