Nicotianamine forms complexes with Zn(ii)in vivo
| Autor: | Wolfram Meyer-Klaucke, Holger Schmidt, Aleksandra Trampczynska, Hendrik Küpper, Stephan Clemens |
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| Rok vydání: | 2010 |
| Předmět: |
Cations
Divalent Biophysics chemistry.chemical_element Zinc Models Biological Biochemistry Biomaterials Metal chemistry.chemical_compound ddc:570 Schizosaccharomyces Transition Elements Hyperaccumulator Nicotianamine Alkyl and Aryl Transferases biology Ligand Metals and Alloys biology.organism_classification Plant cell Thlaspi X-Ray Absorption Spectroscopy chemistry Zinc Compounds Chemistry (miscellaneous) visual_art visual_art.visual_art_medium Azetidinecarboxylic Acid Thlaspi caerulescens |
| Zdroj: | Metallomics. 2:57-66 |
| ISSN: | 1756-591X 1756-5901 |
| DOI: | 10.1039/b913299f |
| Popis: | The non-proteinogenic amino acid nicotianamine (NA) is a major player in plant metal homeostasis. It is known to form complexes with different transition metals in vitro. Available evidence associates NA with translocation of Fe, and possibly other micronutrients, to and between different plant cells and tissues. To date, however, it is still extremely challenging to detect metal-ligand complexes in vivo because tissue disruption immediately changes the chemical environment and thereby the availability of binding partners. In order to overcome this limitation we used various Schizosaccharomyces pombe strains expressing a plant NAS gene to study formation of metal-NA complexes in vivo. Tolerance, accumulation and competition data clearly indicated formation of Zn(ii)-NA but not of Cu(ii)-NA complexes. Zn(ii)-NA was then identified by X-ray absorption spectroscopy (XAS). About half of the cellular Zn was found to be bound by NA in NAS-expressing cells while no NA-like ligands were detected by XAS in control cells not expressing NAS. Given the high conservation of eukaryotic metal homeostasis components, these results strongly suggest the possible existence of Zn(ii)-NA complexes also in planta. Reported observations implicating NA in plant Zn homeostasis would then indeed be attributable to direct interaction of Zn(ii) with NA rather than only indirectly to perturbations in Fe metabolism. Re-evaluation of extended X-ray absorption fine structure (EXAFS) spectra for the Zn hyperaccumulator Thlaspi caerulescens showed that NA is as expected not a major storage ligand for Zn. Instead it is hypothesized to be involved in efficient translocation of Zn to above-ground tissues in hyperaccumulators. |
| Databáze: | OpenAIRE |
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