Comparison of the Nucleotide Sequences of Ferredoxin-cDNAs among some Datura Plants

[Bioinorganic Chemistry of Iron]

　The X-ray crystallographic analysis of the single-crystal mugineic acid-Cu(II) complex showed that mugineic acid acts as a hexadentate ligand. Mugineic acid, a typical phytosiderophore, shows a marked stimulating effect on ⁵⁹Fe-uptake and chlorophyll synthesis in rice plants. A salient feature is the higher reduction potential of the mugineic acid-Fe(III) complex than those of bacterial siderophores. X-ray diffraction study of the structurally analogous Co(III) complex of the mugineic acid-Fe(III) complex demonstrates that the azetidine nitrogen and secondary amine nitrogen, and both terminal carboxylate oxygens, coordinate as basal planar donors, and the hydroxyl oxygen and intermediate carboxylate oxygen bind as axial donors in a nearly octahedral configuration. The iron-transport mechanism in gramineous plants appears to involve the excretion of mugineic acid from the roots, which aids Fe(III)-solubilization and reduction of Fe(III) to Fe(II). Manganese peroxidase (MnP) is a component of the lignin degradation system of the basidiomycetous fungus, Phanerochaete chrysosporium. To elucidate the heme environment of this novel Mn(II)-dependent extracellular enzyme, we studied its ESR and resonance Raman spectroscopic properties. Consequently, it is most likely that the heme environment of MnP resembles that of cytochrome c peroxidase. In addition, degradation methods using basidiomycetous fungi or Fe³⁺-H₂O₂ mixed reagent were developed for dioxins and polychlorinated biphenyls. The complete amino acid sequences of respective [2Fe-2S] ferredoxins were determined and compared with those of other higher plants. Finally, the toxic effects of iron on human health and the development of novel antibacterial drugs capable of inhibiting the iron transport system of Vibrio vulnificus are described.

Amino acid sequences of ferredoxins from Atropa belladonna and Hyoscyamus niger: their similarities to those in other tropane-alkaloid-containing plants

The complete amino acid sequences of [2Fe-2S] ferredoxin from Atropa belladonna and Hyoscyamus niger have been determined by automated Edman degradation of the entire S-carboxymethylcysteinyl proteins and of the peptides obtained by enzymatic digestion. These two ferredoxins exhibited 1-8 differences in their amino acid sequences compared to those of other tropane-alkaloid-containing plants (Scopolia japonica, Datura stramonium, D. metel, and D. arborea), and only 1 or 4 differences compared to S. japonica and D. arborea. In contrast, 9-23 differences were observed among the other solanaceous ferredoxins. This suggests that tropane-alkaloid-containing plants are closely related taxonomically.