Molecular and cellular biology of plant ferritins

The application of a moderate water deficit (water potential of ؊1.3 MPa) to pea (Pisum sativum L. cv Lincoln) leaves led to a 75% inhibition of photosynthesis and to increases in zeaxanthin, malondialdehyde, oxidized proteins, and mitochondrial, cytosolic, and chloroplastic superoxide dismutase activities. Severe water deficit (؊1.9 MPa) almost completely inhibited photosynthesis, decreased chlorophylls, ␤-carotene, neoxanthin, and lutein, and caused further conversion of violaxanthin to zeaxanthin, suggesting damage to the photosynthetic apparatus. There were consistent decreases in antioxidants and pyridine nucleotides, and accumulation of catalytic Fe, malondialdehyde, and oxidized proteins. Paraquat (PQ) treatment led to similar major decreases in photosynthesis, water content, proteins, and most antioxidants, and induced the accumulation of zeaxanthin and damaged proteins. PQ decreased markedly ascorbate, NADPH, ascorbate peroxidase, and chloroplastic Fe-superoxide dismutase activity, and caused major increases in oxidized glutathione, NAD ؉ , NADH, and catalytic Fe. It is concluded that, in cv Lincoln, the increase in catalytic Fe and the lowering of antioxidant protection may be involved in the oxidative damage caused by severe water deficit and PQ, but not necessarily in the incipient stress induced by moderate water deficit. Results also indicate that the tolerance to water deficit in terms of oxidative damage largely depends on the legume cultivar.

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“…3A). This catalytic Fe may be released from Fe-proteins such as phytoferritin, which occurs in the chloroplasts (Briat et al, 1995) (Fig. 5).…”

Section: Discussionmentioning

confidence: 99%

Oxidative Damage in Pea Plants Exposed to Water Deficit or Paraquat1

et al. 1998

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“…The reserves of the metal accumulate in the form of phytoferritin particles in the stroma of plastids (about 35% of total foliar iron) (Abadía, 1992(Abadía, , 1998Briat et al, 1995;Macur et al, 1991;Smith, 1984).…”

Section: Functions Of Iron In Plant Metabolismmentioning

confidence: 99%

Lime-Induced Iron Chlorosis in Fruit Trees

Pestana

Faria

Varennes³

2004

Production Practices and Quality Assessment of Food Crops

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“…Although the primary structures of plant ferritins are basically well conserved with those of mammalian ferritins ( Fig. 1), plant ferritins show two further differences: first, plant ferritin possesses the N-terminal extension regions, which can be divided into two parts based on their functions (37). The upstream one is called a "transit peptide" responsible for transportation of the polypeptide chain to plastid, whereas the downstream one is called an "extension peptide" (EP) with an unknown function (38).…”

mentioning

confidence: 99%

Crystal Structure of Plant Ferritin Reveals a Novel Metal Binding Site That Functions as a Transit Site for Metal Transfer in Ferritin

Masuda

Goto

Yoshihara

et al. 2010

Journal of Biological Chemistry

121

116

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Ferritins are important iron storage and detoxification proteins that are widely distributed in living kingdoms. Because plant ferritin possesses both a ferroxidase site and a ferrihydrite nucleation site, it is a suitable model for studying the mechanism of iron storage in ferritin. This article presents for the first time the crystal structure of a plant ferritin from soybean at 1.8-Å resolution. The soybean ferritin 4 (SFER4) had a high structural similarity to vertebrate ferritin, except for the N-terminal extension region, the C-terminal short helix E, and the end of the BC-loop. Similar to the crystal structures of other ferritins, metal binding sites were observed in the iron entry channel, ferroxidase center, and nucleation site of SFER4. In addition to these conventional sites, a novel metal binding site was discovered intermediate between the iron entry channel and the ferroxidase site. This site was coordinated by the acidic side chain of Glu 173 and carbonyl oxygen of Thr 168 , which correspond, respectively, to Glu 140 and Thr 135 of human H chain ferritin according to their sequences. A comparison of the ferroxidase activities of the native and the E173A mutant of SFER4 clearly showed a delay in the iron oxidation rate of the mutant. This indicated that the glutamate residue functions as a transit site of iron from the 3-fold entry channel to the ferroxidase site, which may be universal among ferritins.

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Molecular and cellular biology of plant ferritins

Cited by 16 publications

References 64 publications

Oxidative Damage in Pea Plants Exposed to Water Deficit or Paraquat1

Oxidative Damage in Pea Plants Exposed to Water Deficit or Paraquat1

Lime-Induced Iron Chlorosis in Fruit Trees

Crystal Structure of Plant Ferritin Reveals a Novel Metal Binding Site That Functions as a Transit Site for Metal Transfer in Ferritin

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