• Journal of Microbiology and Biotechnology
• /
• v.14 no.1
• /
• pp.68-73
• /
• 2004

Ferritin is an iron storage protein found in most living organisms. For expression and industrial use, human light chain ferritin (L-ferritin) was cloned from human liver cDNA library and expressed in Pichia pastoris strain GS115. The recombinant L-ferritin in Pichia pastoris was glycosylated. In a fed-batch culture, the cell mass reached about 57 g/l of dry cell weight, and the L-ferritin in the cell was increased to about 95 mg/l after 150 h. In an atomic absorption spectrometry analysis, the intracellular content of iron in the L-ferritin transformant was measured as $1,694{\pm}85\;\mu\textrm{g}g/g$, which is 5.4-fold more than that of the control strain. This L-ferritin transformant could serve as iron-fortified nutrients in animal feed stock.

• KSBB Journal
• /
• v.26 no.2
• /
• pp.119-125
• /
• 2011

In the synthesis of nanoparticles, much attention has been paid to regulating the particle size. There has been a possible evident that using the central cavity (core) of the protein ferritin has a greatly significant influence on it because the core can generate the nanometer-sized mineral particles of variable metal ions. In this report, recombinant human L-ferritins produced from Saccharomyces cerevisiae were purified and their molecular properties were characterized. The cDNA for human ferritin L chain was also expressed in another host such as Escherichia coli, and the properties of recombinant L-ferritins were compared. From isoelectric focusing experiment, the L-ferritin from the recombinant yeast showed no indication of N-glycosylation. Some post-translational modifications other than N-glycosylation were speculated in the L-ferritins from yeast. A difference was made in the L-ferritins in their iron uptake rates and the initial rate of the L-ferritin from yeast was slightly increased. The reconstitution yield and size distribution of the core minerals were analyzed in the L-ferritins by transmission electron microscopy. The L-ferritin from yeast with higher reconstitution yield (54.5%) showed slightly larger sizes (mean 6.92 nm) with narrower size distribution than the L-ferritin from E. coli. It is, in conclusion, speculated that L-ferritin from yeast is relatively superior to the other, in view of the size of nanoparticle and its relative homogeneity.

• KSBB Journal
• /
• v.17 no.2
• /
• pp.162-168
• /
• 2002

Human ferritin H- and L-chain genes(hfH and hfL) were cloned into the yeast shuttle vector YEp352 with various promoters, and the vectors constructed were used to transform Saccharomyces cerevisiae 2805. Three different promoters fused to hfH and hfL were used: galactokinase 1 (GAL1) promoter, glyceraldehyde-3-phosphate dehydrogenase(GPD) promoter and alcohol dehydrogenase 1(ADH1 ) promoter. SDS-polyacrylamide gel electrophoresis and Western blotting analyses displayed expression of the introduced hfH and hfL. In the production of both ferritin H and L subunits GAL1 promoter was more effective than GPD promoter or ADH1 promoter. Ferritin H and L subunits produced in S. cerevisiae were spontaneously assembled into its holoproteins as proven on native polyacrylamide gels. Both recombinant H and L-chain ferritins were catalytically active in forming iron core. When the cells were cultured in the medium containing 10 mM ferric citrate, the cell-associated concentration of iron was 174.9 $\mu\textrm{g}$ Per gram(dry cell weight) for the recombinant yeast YG-L and 148.8 $\mu\textrm{g}$ Per gram(dry cell weight) for the recombinant yeast YG-L but was 49.4 $\mu\textrm{g}$ Per gram(dry cell weight) in the wild type, indicating that the iron contents of yeast is improved by heterologous expression of human ferritin H-chain or L-chain genes.

• KSBB Journal
• /
• v.17 no.4
• /
• pp.365-369
• /
• 2002

An iron-storage protein, ferritin is a spherical shell consisting of 24 H-and L-chain subunits. Soluble form of fused($F_{H}+F_{L}$ chain) ferritin was separated from disrupted recombinant E. coii cells, followed by silica powder adsorption. Ferritin was recovered from silica-poweder by distilled water, which was applied to gel filtration chromatography(GFC). Collected ferritin fractions from the GFC were assayed via iron-uptake and its molecular weight determined using GF-HPLC. Fused ferritin showed a higher activity than the M- or L- chain ferritin by two times.

• KSBB Journal
• /
• v.19 no.5
• /
• pp.352-357
• /
• 2004

Human ferritin H- and L-chain genes (hfH and hfL) were cloned into the yeast shuttle vector YEp352 containing the GAL1 (galactokinase) and GAL10 (epimerase) divergent promoters and the vectors constructed were used to transform Saccharomyces cerevisiae 2805. SDS-PAGE displayed expression of the introduced hfH and hfL in both recombinant strains of Y1H10L and Y1L10H. The ferritin subunits, that represented ca. $22\%$ and $15\%$ of the soluble proteins in Y1H10L and Y1L10H, were spontaneously assembled into active ferritin heteropolymers. The H subunit content of the purified recombinant human ferritin heteropolymers was proven to reflect the relative expression yield of the subunits. When the cells of 2d culture were incubated with 14.3 mM Fe(2), the cellular iron concentration of Y1H10L and Y1L10H was 1.7 and 2.0 times, respectively, that of the control strain. It is assumed that increase in the iron uptake of the recombinant yeasts is closely related to ferritin expression and H subunit content.

• BMB Reports
• /
• v.28 no.3
• /
• pp.238-242
• /
• 1995

The tadpole H-ferritin produced in E. coli was purified and its molecular properties were investigated to obtain information about the contribution of the H-subunit in the reaction of iron core formation. All the expressed subunits were assembled into complete holoprotein in vitro, presumably 24-mer, and the protein was heat-stable. Electron microscopy revealed that the recombinant ferritin forms spherically and contains iron core. No difference was observed in the absorption spectrum of the expressed protein compared to that of the natural ferritin. The Ouchterlony double diffusion of the expressed protein showed that the H-chain ferritin shares an antigenic determinant with natural tadpole ferritin. Rabbit anti-horse spleen ferritin discriminated the H-ferritin from natural ferritin. The rate of ferritin formation by the recombinant H-chain apoferritin was determined to be higher than that shown by natural tadpole ferritin, which consists of H, M and L-subunits. This phenomenon may be caused by the absence of M and L-subunits in the recombinant H-chain apoferritin.

• Korean Journal of Plant Tissue Culture
• /
• v.28 no.3
• /
• pp.147-151
• /
• 2001

Explants of Lactuce sativa cultivar, chungchima, were co-cultivated with Agrobacterium tumefaciences LBA4404, EHA101 strains containing nptll gene and ferritin gene encoding iron storage protein from soybean for transformation. Through initial selection of regenerated explants by culturing on a kanamycin and carbenicillin containing MS medium, multiple shoots were obtained after 2 months of culture. For a complementary step of selection, putative transgenic shoots were transferred to 1/2 MS basal medium supplemented with 100 mg/L kanamycin and 500 mg/L carbenicillin. The selected shoots were tested with PCR analysis using nptll, ferritin specific primers whether ferritin gene was introduced to genome of the plants. These results confirmed that produced the specific PCR bands in the putative transgenic lines. Additionally the Northern blot showed that transcripts of ferritin gene were detected in mature leaf of the transgenic lines. These results suggest that ferritin gene be successfully integrated and transcribed in the putative transgenic lettuce plants.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.5
• /
• pp.926-932
• /
• 2008

Human heavy chain (H-) and light chain (L-) ferritins were amplified from a human cDNA library. Each ferritin gene was inserted downstream of the T7 promoter of bacterial expression vectors, and two types of coexpression vectors were constructed. The expression levels of recombinant ferritins ranged about 26-36% of whole-cell protein. H-ferritin exhibited a lower expression ratio compared with L-ferritin, by a coexpression system. However, the coexpression of HL-ferritins was significantly increased above the expression ratio of H-ferritin by cultivation without IPTG induction overnight. Purified recombinant H-, L-, HL-, and LH-ferritins were shown to be homo- and heteropolymeric high molecular complexes and it was indicated that their assembled subunits would be able to work functionally in the cell. Thus, these results indicate an improvement in the expression strategy of H-ferritin for heteropolymeric production and studies of ferritin assembly in Escherichia coli.

• Microbiology and Biotechnology Letters
• /
• v.36 no.3
• /
• pp.221-226
• /
• 2008

To produce human ferritins in yeast, human H-chain and L-chain ferritins were amplified from previously cloned vectors. Each amplified ferritin gene was inserted into the pYES2.1/V5-His-TOPO yeast expression vector under the control of the GAL1promoter. Western blot analysis of the recombinant yeast cells revealed that H-and L-chain subunits of human ferritin were expressed in Saccharomyces cerevisiae. Atomic absorption spectrometry (AAS) analysis demonstrated that the intracellular content of iron in the ferritin transformant was 1.6 to 1.8-fold higher than that of the control strain. Ferritin transformants could potentially supply iron-fortified nutrients for food and feed.

• BMB Reports
• /
• v.34 no.4
• /
• pp.365-370
• /
• 2001

We constructed a comparative expression system in order to produce recombinant human ferritin homo- and heteropolymers in Escherichia coli. Human ferritin H-(hfH) and L-chain (hfL) genes were expressed without amino acid changes under the control of a tac promoter. Ferritin heteropolymers of varying subunit composition were also produced by combining two different expression systems, a bicistronic expression system and a coplasmid expression system. As a result, recombinant H-chain ferritin and ferritin heteropolymers were catalytically active in forming iron core in vivo. In particular, the ferritin heteropolymer that is composed of 7% H-subunit and 93% L-subunit was capable of forming an iron core of the protein, while the L-chain ferritin homopolymer was inactive in vivo. This result indicates that the two H-subunits (i.e., 7% H-subunit content) are important to keep ferritin active in the cells. In addition, human ferritins were identified as the major iron binding proteins in the transformed cells. Also, the amount of iron bound to the recombinant ferritins was proportional to the H-subunit content in ferritin heteropolymers in vivo.