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Characterization of Arabidopsis thaliana SufE2 and SufE3: functions in chloroplast iron-sulfur cluster assembly and Nad synthesis.
- Source :
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The Journal of biological chemistry [J Biol Chem] 2007 Jun 22; Vol. 282 (25), pp. 18254-18264. Date of Electronic Publication: 2007 Apr 23. - Publication Year :
- 2007
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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.
- Subjects :
- Arabidopsis Proteins metabolism
Carbon-Sulfur Lyases metabolism
DNA, Bacterial metabolism
Electron Spin Resonance Spectroscopy
Escherichia coli metabolism
Genetic Complementation Test
Oligonucleotides chemistry
Plasmids metabolism
Plastids metabolism
Pollen metabolism
Protein Binding
Protein Structure, Tertiary
Arabidopsis metabolism
Arabidopsis Proteins physiology
Chloroplasts metabolism
Iron-Sulfur Proteins chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 282
- Issue :
- 25
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 17452319
- Full Text :
- https://doi.org/10.1074/jbc.M701428200