Characterization of Arabidopsis thaliana SufE2 and SufE3: functions in chloroplast iron-sulfur cluster assembly and Nad synthesis.
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.
M
Narayana Murthy U
NMU
Biology Department and Program in Molecular Plant Biology, Colorado State University, Fort Collins, Colorado 80523.
Ollagnier-de-Choudens
Sandrine
S
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.
Sanakis
Yiannis
Y
NCSR, Demokritos, Institute of Materials Science, 15310 Ag. Paraskevi, Attiki, Greece.
Abdel-Ghany
Salah E
SE
Biology Department and Program in Molecular Plant Biology, Colorado State University, Fort Collins, Colorado 80523.
Rousset
Carine
C
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.
Ye
Hong
H
Biology Department and Program in Molecular Plant Biology, Colorado State University, Fort Collins, Colorado 80523.
Fontecave
Marc
M
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.
Pilon-Smits
Elizabeth A H
EAH
Biology Department and Program in Molecular Plant Biology, Colorado State University, Fort Collins, Colorado 80523.
Pilon
Marinus
M
Biology Department and Program in Molecular Plant Biology, Colorado State University, Fort Collins, Colorado 80523. Electronic address: pilon@lamar.colostate.edu.
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
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