High-resolution 1H NMR analysis of solution structures and conformational properties of mugineic acid and its metal complexes

Iwashita, Takashi; Mino, Yoshiki; Naoki, Hideo; Nomoto, Kyosuke

doi:10.1021/bi00289a034

Cited by 21 publications

(7 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Sugiura et al (1981) estimated the formation constants for PS complexation with Fe(III), Cu(II), Zn(II) and Fe(II) as (log K=) 18.1, 18.3, 10.7 and 8.1, respectively. Nuclear magnetic resonance studies by Iwashita et al (1983) indicate that there are clear conformational dierences between PS-Zn(II) and PS-Co(III) [the latter being an analog for the PS-Fe(III) complex ]. The PS-Fe(III) complex is taken up at least ®ve times faster than other PS-trace metal complexes ).…”

Section: Discussionmentioning

confidence: 99%

Zinc deficiency-induced phytosiderophore release by the Triticaceae is not consistently expressed in solution culture

Pedler

Parker

Crowley

2000

Planta

View full text Add to dashboard Cite

The effects of zinc (Zn) and iron (Fe) deficiencies on phytosiderophore (PS) exudation by three barley (Hordeum vulgare L.) cultivars differing in Zn efficiency were assessed using chelator-buffered nutrient solutions. A similar study was carried out with four wheat (Triticum aestivum L. and T. durum Desf.) cultivars, including the Zn-efficient Aroona and Zn-inefficient Durati. Despite severe Zn deficiency, none of the barley or wheat cultivars studied exhibited significantly elevated PS release rates, although there was significantly enhanced PS exudation under Fe deficiency. Aroona and Durati wheats were grown in a further study of the effects of phosphate (P) supply on PS release, using 100 microM KH2PO4 as high P, or solid hydroxyapatite as a supply of low-release P. Phytosiderophore exudation was not increased due to P treatment under control or Zn-deficient conditions, but was increased by Fe deficiency. Accumulation of P in shoots of Zn- and Fe-deficient plants was seen in both P treatments, somewhat more so under the KH2PO4 treatment. Zinc-efficient wheats and grasses have been previously shown to exude more PS under Zn deficiency than Zn-inefficient genotypes. We did not observe Zn-deficiency-induced PS release and were unable to replicate the results of previous researchers. The tendency for Zn deficiency to induce PS release seems to be method dependent, and we suggest that all reported instances may be explained by an induced physiological deficiency of Fe.

show abstract

Section: Discussionmentioning

confidence: 99%

Zinc deficiency-induced phytosiderophore release by the Triticaceae is not consistently expressed in solution culture

Pedler

Parker

Crowley

2000

Planta

View full text Add to dashboard Cite

show abstract

“…To further examine whether DMA can form a complex with Al 3 + or not, 1 H-NMR study was conducted on the solution of an equimolar mixture of DMA and Al 3 + . The DMA-Zn 2 + complex was used for comparison because DMA coordinates with Zn 2 + in a hexadentate fashion by six functional groups (two amino, three carboxyl, and terminal hydroxyl groups) (Iwashita et al 1983). Compared to the proton chemical shifts of DMA alone, formation of the DMA-Zn 2 + complex resulted in a change of the proton chemical shifts of DMA (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…1 H-NMR spectra of the complex were recorded on a 500 MHz spectrometer (DMX 500). Assignment of 1 H was accomplished according to Iwashita et al (1983).…”

Section: Spectroscopic and Nmr Studiesmentioning

confidence: 99%

Effect of Al on the phytosiderophore‐mediated solubilization of Fe and uptake of Fe‐phytosiderophore complex in wheat (Triticum aestivum)

Chang

Feng

Iwashita

et al. 1999

Physiologia Plantarum

Self Cite

View full text Add to dashboard Cite

The effect of Aluminum (Al) on phytosiderophore‐mediated solubilization of insoluble Fe and the uptake of phytosiderophore‐Fe3+ complex was examined in wheat (Triticum aestivum L. cv. Atlas 66). Al addition did not affect the Fe solubilization by 2′‐deoxymugineic acid (DMA), although Cu addition significantly inhibited the solubilization capacity. Addition of ten times more Al than Fe to the solution of DMA‐Fe3+ complex did not decrease the absorption of the DMA‐Fe3+ complex at 375 nm. Furthermore, NMR study indicated that Al did not shift the proton chemical shifts of DMA. All these results suggest that Al could not form a complex with the phytosiderophore, and is thereby unlikely to affect the process of phytosiderophore‐mediated solubilization of Fe. Exposure of root to Al up to 100 μM for 3 h did not inhibit the DMA‐Fe3+ uptake by the roots, but longer pretreatment (>6 h) inhibited the uptake of the DMA‐Fe3+ by more than 50%. Neither the uptake of DMA‐Fe3+ nor root elongation was inhibited by 24 h pretreatment with 10 μM Al, but both uptake and root elongation were inhibited by higher Al (>20 μM) pretreatment. These results suggest that Al did not directly block the transport of the phytosiderophore‐Fe3+ complex, and that the decreased uptake of the phytosiderophore‐Fe3+ complex resulted from the roots being damaged by Al.

show abstract

“…The complexation of iron(III) by mugineic acids has already been investigated in some detail by NMR [13,14], ESR [14], and Mössbauer spectroscopy [12]; this work has included the determination of stability constants [12,14], study of electrochemical behavior [12], and the conformation in solution has even been proposed [26]. These investigations were, however, only model experiments performed at relatively high concentrations.…”

Section: Detection Of Fe Species Of Phytosiderophoresmentioning

confidence: 99%

“…The direct determination of the intact Fe-phytosiderophore-chelate, however, has not yet been achieved. Model experiments, at higher concentrations, have been performed with the intention of elucidation of the structure of the Fe-mugineic acid complex [4,9,12,13,14]. In the work discussed in this paper at least two different iron-phytosiderophore complexes were identified in the µmol L -1 concentration range after anionexchange chromatography by using PAD and AAS in parallel as selective detectors for phytosiderophores and iron, respectively.…”

Section: Introductionmentioning

confidence: 99%

Speciation of iron coordinated by phytosiderophores by use of HPLC with pulsed amperometric detection and AAS

2002

View full text Add to dashboard Cite

Phytosiderophores of the mugineic acid family, and the respective iron species, have been separated by anion-exchange chromatography with NaOH gradient elution. Two different detection methods were used in parallel, pulsed amperometry (PAD) for phytosiderophores and atomic absorption spectrometry (AAS) for iron. This combination enables identification of separated iron species. Up to five different iron species were separated and detected within 30 min - two different phytosiderophore species, two amino acid species, and one species which has not yet been identified but which is most probably a decomposition product of phytosiderophores. The detection limit was in the low micro mol L(-1) concentration range, which is sufficiently low for determination in real plant samples, even after dilution. The method has been applied to root washings of iron-deficient wheat and barley plants and to a xylem exudate of non-deficient maize.

show abstract

High-resolution 1H NMR analysis of solution structures and conformational properties of mugineic acid and its metal complexes

Cited by 21 publications

References 13 publications

Zinc deficiency-induced phytosiderophore release by the Triticaceae is not consistently expressed in solution culture

Zinc deficiency-induced phytosiderophore release by the Triticaceae is not consistently expressed in solution culture

Effect of Al on the phytosiderophore‐mediated solubilization of Fe and uptake of Fe‐phytosiderophore complex in wheat (Triticum aestivum)

Speciation of iron coordinated by phytosiderophores by use of HPLC with pulsed amperometric detection and AAS

Contact Info

Product

Resources

About