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Heavy metal ions pollution can cause damage to human body through food, so the development of a new kind of macromolecular that can remove heavy metal ions damage has a good application prospect. The possibilities of removing heavy metal ions from food system with ferritin were studied in this paper. In this study, oyster ferritin (GF1) can resistant to denaturation induced by Pb2+, Cd2+, Cr3+ and still maintains its basic structure. GF1 can bind more Pb2+, Cd2+, Cr3+ than recombinant human H-chain ferritin (rHuHF), especially Pb2+, and the findings suggest that each GF1 can capture about 51.42 Pb2+ in solution. The hard and soft acids and base also verifies that Pb2+ have stronger binding ability to the key amino acids at the outer end of the three-fold symmetry channel. Cells preprotected by ferritin could resistant to heavy metal ions. And GF1 can reduce the high blood lead in mice and may play a role in alleviating lead poisoning in vivo. All findings demonstrated that GF1 can be used as a novel macromolecule to bind heavy metal ions, and the study can broaden the research scope of ferritin in contaminated food systems. [Display omitted] • Oyster ferritin can maintain certain structural and physiological activities upon treatment with Pb2+, Cd2+ and Cr3+. • Oyster ferritin can bind more Pb2+ than recombination human heavy chain ferritin. • Oyster ferritin can significantly reduced blood lead levels in mice. [ABSTRACT FROM AUTHOR]

Ferritin can form nanocage architectures and has demonstrated potential to serve as functional nanomaterials. Here, the oyster (Crassostrea gigas) ferritin gene GF1 was obtained from the viscera of the oyster, successfully cloned, prokaryotically expressed in E. coli BL21 (DE3), purified and characterized. Oyster ferritin was purified by ion exchange chromatography using DEAE-Sepharose Fast Flow. The molecular weight of the subunit was 19972 Da (polyacrylamide gel electrophoresis), and the oyster ferritin weight was 480 kDa (non-denaturing gel electrophoresis). After in-gel trypsin digestion, ferritin was identified using NanoLC-Q-TOF-MS and then analyzed by circular dichroism (CD) spectrometry for its secondary structure. Ferritin nanocages were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The three-dimensional structure of oyster ferritin was constructed based on the amino acid sequence of human ferritin heavy chain by the homology modeling method. Here, we provide a theoretical foundation for ferritin self-assembly and biological functional activity. Image 1 • The recombinant oyster ferritin was firstly purified and characterized. • Oyster ferritin 24 subunits can self-assemble into spherical shells. • The three-dimensional structure of subunit and spherical shell was reported. [ABSTRACT FROM AUTHOR]

Lead can induce oxidative stress and increase lipid peroxidation in biofilms, leading to liver damage and physiological dysfunction. This study aimed to investigate how oyster ferritin (GF1) attenuates lead-induced oxidative damage to the liver in vitro and in vivo. Animal experiments have confirmed that lead exposure can lead to oxidative damage and lipid peroxidation of the liver, and ferritin can regulate the activity of antioxidant enzymes and alleviate pathological changes in the liver. At the same time, oyster ferritin can regulate the expression of oxidative stress-related genes and reduce the expression of inflammasome-related genes. In addition, lead can induce apoptosis and mitophagy, leading to overproduction of reactive oxygen species and cell death, which can be effectively alleviated by oyster ferritin. Overall, this study provides a theoretical foundation for the use of oyster ferritin as a means of mitigating and preventing lead-induced damage. • Oyster can regulate the activity of antioxidant enzymes and alleviate pathological changes in the liver. • Oyster ferritin can regulate the expression of oxidative stress-related genes and inflammasome-related genes. • Oyster ferritin can effectively alleviate lead-induced apoptosis and mitochondrial autophagy in LO2 cells. [ABSTRACT FROM AUTHOR]

• After adding about 1000 Fe2+ in vitro , oyster ferritin reached the saturation state. • Adding Fe2+ can improve the storage and thermal stability of oyster ferritin. • Heating at 80 ℃ and below does not affect the structure and Fe2+ content of GF1-1000 Fe2+. Ferritin, one of the storage forms of iron, which widely exists in all living organisms and shows its potential as functional nanomaterial. In this study, Fe2+ were added to oyster ferritin (GF1) in vitro until reached experimental saturation state. The structure characterization and monodisperse morphology of ferritin were showed that the protein structure of ferritin did not change significantly after adding Fe2+ and GF1 with 1000 Fe2+ (GF1-1000 Fe2+) was selected for subsequent experiments. The storage stability results showed that 11.27 % of the protein remained cage-like structure when GF1-1000 Fe2+ was stored at 4 °C for 12 days. The thermal treatment results showed that GF1-1000 Fe2+ still maintained certain structure and activity at 80 °C, and 82.8 % of Fe2+ was still retained at 80 °C. These experimental results may provide a theoretical basis for the development of novel iron supplement that are non-toxic and highly stable. [ABSTRACT FROM AUTHOR]

• Point mutation in D120G could improve the thermal stability of oyster ferritin. • The spherical shell of mutated ferritin can be kept well at 90 °C and below. • The stability of oyster ferritin was promoted via the improved 3-fold interfaces. Ferritin can be widely used as functional nanomaterial. But the physiological activity of ferritin can be damaged under excessive temperatures, which affect the self-assembly property. In this study, point mutation was produced in Asp120 to Gly120 of ferritin amino acid sequence and the heat resistance was improved significantly. The thermal denaturation temperature of mutated ferritin is 89.17 °C and has increased by 13 °C more than the wild-type oyster ferritin. The effect of thermal treatment on the denaturation, aggregation state, particle size and the structure of ferritin was not changed before 90 °C. The computational modeling and analysis indicated that mutated ferritin promotes the overall structural stability assembly via decreasing the interaction energies of 62 percent energies in 3-fold interface. Improving the thermal stability of oyster ferritin by point mutation enhances its applications as a food ingredient. [ABSTRACT FROM AUTHOR]

• Thermal treatment could induce denaturation and aggregation of oyster ferritin. • The ferritin spherical shell destroyed gradually and could not be observed at 100 °C. • Thermal treatment could change the structure of oyster ferritin. The unique nanocage structure of ferritin can be used as functional nanomaterials and has wide application prospects. However, thermal treatment may affect the structure of ferritin, further affecting self-assembly property. In this study, the oyster ferritin gene GF1 was obtained, prokaryotically expressed in E. coli BL21 (DE3). Then the purified ferritin was heated from 60 to 100 °C for 10 min with untreated ferritin as a control sample. The aggregation state of ferritin was investigated and the difference in protein structure was evaluated in terms of particle size and protein structures. The results of electrophoresis indicated that thermal treatment induced denaturation and aggregation of ferritin macromolecules. Moreover, the particle size distribution shifted to larger size trend and aggregates were visible with the heated samples and the secondary structure and tertiary structure were destroyed gradually. The findings are beneficial for understanding the relationship of the structure and function of ferritin. [ABSTRACT FROM AUTHOR]