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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have constructed a random nonapeptide library in the N-terminal region of the major coat protein VIII of bacteriophage f1, with two cysteines flanking the insert, and preliminary data suggest that many of the clones display at least some of their peptides in cyclized form. This library was used to select oligopeptides binding to the monoclonal antibody (mAb) H107, recognising the assembled native conformation of recombinant human H-subunit ferritin (H Fer), whose three-dimensional structure is known. Comparison of the selected oligopeptides with one another allowed us to derive two consensus sequences characterized by conserved amino acid (aa) residues. Analysis of the distribution of the aa side chains exposed on the surface of H Fer reveals that most of the aa defining both consensus sequences are present either at the end of the big loop or at the end of the A helix. These two regions of the H Fer, though separated in the linear sequence, are very close in the folded molecule. Interestingly, each consensus sequence derived from the selected phage-displayed peptides is characterized by aa present both at the end of the big loop and at the end of the A helix. These two H Fer regions are good candidates for mimicry by the selected peptides and therefore for constituting part of the H107 epitope. To provide support to this hypothesis, we constructed several H Fer mutants carrying point mutations in different positions of these two regions.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Mimicking of discontinuous epitopes by phage-displayed peptides, I. Epitope mapping of human H ferritin using a phage library of constrained peptides. 768 1

Regular blood donors were enrolled in a double-blind, parallel group study to evaluate the side effects of two iron supplements, one containing both heme iron and non-heme iron (Hemofer, 2 tablets = 18 mg iron/day), the other non-heme iron only (Erco-Fer; 1 tablet = 60 mg iron/day). No differences were found between the two alternatives in regaining predonation iron status as measured by serum ferritin and hemoglobin levels. Despite this therapeutic equivalence, participants' symptom diaries showed substantial differences in the side effects for the two treatments. The frequency of constipation (p < 0.05) and the total incidence of all side effects (p < 0.01) were significantly higher for non-heme iron when compared with the heme iron-non-heme iron combination and a placebo. The study demonstrates that a low-dose iron supplement containing both heme iron and non-heme iron (Hemofer) has fewer side effects when compared with an equipotent, traditional non-heme iron supplement.
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PMID:Side effects of iron supplements in blood donors: superior tolerance of heme iron. 814 4

Complete blood counts and levels of ferritin in serum (S-Fer) in 62 college students were analyzed continuously to clarify the effects of blood donation. In 14 (45%) of 31 females, hemoglobin (Hb) and S-Fer levels showed decrease of more than 5% and 30%, respectively, four weeks after donation of 200ml or 400ml of blood. In 11 (35%) of the males and 6% of the females, Hb levels increased over 5% during the same period. In 61% of the males and 45% of the females, S-Fer levels decreased. In only 19% of the males, the Hb and S-Fer levels were unchanged. Red blood cell (RBC) counts and Hb levels showed almost the same pattern. In 39% of the males and 48% of the females, the white blood cell (WBC) counts decreased more than 10%. In 10% of the males and 23% of the females, WBC counts increased more than 10% after blood donation. The WBC and RBC counts did not always show the same pattern of variation. After blood donation, the incidence of iron deficiency anemia among females increased from 13% to 23% and the incidence of latent iron deficiency among females increased from 10% to 42%.
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PMID:[The states of recovery of blood counts and serum ferritin levels after blood donation]. 828 4

An iron supplement was given to female blood donors to prevent iron deficiency after blood donation. The levels of items related to red blood cells and serum ferritin (S-Fer) among 17 iron-takers and 31 non-iron-takers were analyzed continuously. In most of the non-iron-takers, the S-Fer levels did not recover within four weeks after the donation of 200ml or 400ml of blood. In the approximately half of the donors, hemoglobin (Hb) levels did not recover either. However, in 59% of those taking iron supplements three times the amount of iron lost by donation, the levels of Hb and S-Fer recovered within two weeks. In the remaining 41%, the Hb levels recovered within four weeks by taking the iron supplement. Four weeks after blood donation, the incidence of iron deficiency anemia among the non-iron-takers increased from 13% to 23% and the incidence of latent iron deficiency among the non-iron-takers increased from 32% to 42%. However, the incidence of iron deficiency anemia among the iron-takers remained 0% and the incidence of latent iron deficiency among the iron-takers decreased from 12% to 6%.
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PMID:[Recovered state of iron in female blood donors--after taking an iron supplement]. 855 82

Rat liver DT-diaphorase (EC 1.6.99.2) catalyzed reductive N-denitration of tetryl (2,4,6-tri-nitrophenyl-N-methylnitramine) and 2,4-dinitrophenyl-N-methylnitramine, oxidizing the excess of NADPH. The reactions were accompanied by oxygen consumption and superoxide dismutase-sensitive reduction of added cytochrome c and reductive release of Fe2+ from ferritin. Quantitatively, the reactions of DT-diaphorase proceeded like single-electron reductive N-denitration of tetryl by ferredoxin:NADP+ reductase (EC 1.18.1.2) (Shah, M.M. and Spain, J.C. (1996) Biochem. Biophys. Res. Commun. 220, 563-568), which was additionally checked up in this work. Thus, although reductive N-denitration of nitrophenyl-N-nitramines is a net two-electron (hydride) transfer process, DT-diaphorase catalyzed the reaction in a single-electron way. These data point out the possibility of single-electron transfer steps during obligatory two-electron (hydride) reduction of quinones and nitroaromatics by DT-diaphorase.
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PMID:DT-diaphorase catalyzes N-denitration and redox cycling of tetryl. 978 67

Iron is an essential nutrient for nearly all organisms but presents problems of toxicity, poor solubility and low availability. These problems are alleviated through the use of iron-storage proteins. Bacteria possess two types of iron-storage protein, the haem-containing bacterioferritins and the haem-free ferritins. These proteins are widespread in bacteria, with at least 39 examples known so far in eubacteria and archaebacteria. The bacterioferritins and ferritins are distantly related but retain similar structural and functional properties. Both are composed of 24 identical or similar subunits (approximately 19 kDa) that form a roughly spherical protein (approximately 450 kDa, approximately 120 A diameter) containing a large hollow centre (approximately 80 A diameter). The hollow centre acts as an iron-storage cavity with the capacity to accommodate at least 2000 iron atoms in the form of a ferric-hydroxyphosphate core. Each subunit contains a four-helix bundle which carries the active site or ferroxidase centre of the protein. The ferroxidase centres endow ferrous-iron-oxidizing activity and are able to form a di-iron species that is an intermediate in the iron uptake, oxidation and core formation process. Bacterioferritins contain up to 12 protoporphyrin IX haem groups located at the two-fold interfaces between pairs of two-fold related subunits. The role of the haem is unknown, although it may be involved in mediating iron-core reduction and iron release. Some bacterioferritins are composed of two subunit types, one conferring haem-binding ability (alpha) and the other (beta) bestowing ferroxidase activity. Bacterioferritin genes are often adjacent to genes encoding a small [2Fe-2S]-ferredoxin (bacterioferritin-associated ferredoxin or Bfd). Bfd may directly interact with bacterioferritin and could be involved in releasing iron from (or delivering iron to) bacterioferritin or other iron complexes. Some bacteria contain two bacterioferritin subunits, or two ferritin subunits, that in most cases co-assemble. Others possess both a bacterioferritin and a ferritin, while some appear to lack any type of iron-storage protein. The reason for these differences is not understood. Studies on ferritin mutants have shown that ferritin enhances growth during iron starvation and is also involved in iron accumulation in the stationary phase of growth. The ferritin of Campylobacter jejuni is involved in redox stress resistance, although this does not appear to be the case for Escherichia coli ferritin (FtnA). No phenotype has been determined for E. coli bacterioferritin mutants and the precise role of bacterioferritin in E. coli remains uncertain.
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PMID:Iron storage in bacteria. 988 81

Our previous work showed that immunization of mice with Schistosoma japonicum (Sj) immature eggs induced significant immunity against fecundity and embryonation of the parasite. The Sj adult cDNA library was screened by sera from rabbits against Sj immature egg antigen (RASjIEA). The genes encoding molecules which may induce immunity against fecundity/embryonation were chosen for further cloning and expression. First of all, RASjIEA was absorbed with E. coli lysate to remove cross reactive antibodies. The cDNA library was then immunoscreened using the routine method. The resulted positive plaques were rescreened till individual clones were confirmed. Phagemids were obtained using in vivo excision. The positive clones were amplified using PCR. The sizes of the genes were determined by agarose gel electrophoresis. After DNA sequencing of the genes cloned, Gene bank was searched and six different genes were identified from a total of 102 positive clones. One of six identified genes, Sj ferritin (SjFer) was chosen to subclone into pGMC vector. According to DNA sequences of Sj Fer and MCS (multiple cloning site) of the vector, forward primer (Fer/GMC1) and reverse primer (Fer/GMC2) were designed and used to amplify Sj Fer by PCR. The Sj Fer cDNA and expression vector pGMC were digested with BamHI and XhoI. The digested cDNA and pGMC were ligased by T4 DNA ligase to construct a recombinant which was then used to transform E. coli strain ER2566. The fusion protein GMCSF-Sj Ferritin was expressed in insoluble form, the inclusion body. Pellets were harvested and resolved in Tris-HCl buffer containing 8M urea. GMCSF-Sj Ferritin was purified by affinity chromatography using Ni-NTA resin. The molecular weight was determined by SDS-PAGE. This study first reports the gene encoding S. japonicum ferritin as a new candidate for schistosome vaccine.
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PMID:[Schistosoma japonicum ferritin: cloning, nucleotide sequencing, expression, and purification]. 1068 50

We report a method for detection of recurring side-chain patterns (DRESPAT) using an unbiased and automated graph theoretic approach. We first list all structural patterns as sub-graphs where the protein is represented as a graph. The patterns from proteins are compared pair-wise to detect patterns common to a protein pair based on content and geometry criteria. The recurring pattern is then detected using an automated search algorithm from the all-against-all pair-wise comparison data of proteins. Intra-protein pattern comparison data are used to enable detection of patterns recurring within a protein. A method has been proposed for empirical calculation of statistical significance of recurring pattern. The method was tested on 17 protein sets of varying size, composed of non-redundant representatives from SCOP superfamilies. Recurring patterns in serine proteases, cysteine proteases, lipases, cupredoxin, ferredoxin, ferritin, cytochrome c, aspartoyl proteases, peroxidases, phospholipase A2, endonuclease, SH3 domain, EF-hand and lectins show additional residues conserved in the vicinity of the known functional sites. On the basis of the recurring patterns in ferritin, EF-hand and lectins, we could separate proteins or domains that are structurally similar yet different in metal ion-binding characteristics. In addition, novel recurring patterns were observed in glutathione-S-transferase, phospholipase A2 and ferredoxin with potential structural/functional roles. The results are discussed in relation to the known functional sites in each family. Between 2000 and 50,000 patterns were enumerated from each protein with between ten and 500 patterns detected as common to an evolutionarily related protein pair. Our results show that unbiased extraction of functional site pattern is not feasible from an evolutionarily related protein pair but is feasible from protein sets comprising five or more proteins. The DRESPAT method does not require a user-defined pattern, size or location of the pattern and therefore, has the potential to uncover new functional sites in protein families.
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PMID:Functional sites in protein families uncovered via an objective and automated graph theoretic approach. 1258 52

A tungsten-binding protein was purified from a plasma membrane preparation of the iron-oxidizing bacterium, Acidithiobacillus ferrooxidans AP19-3 in an electrophoretically homogenous state. The protein was composed of two subunits with apparent molecular masses of 12 and 20.7 kDa. The molecular mass of the native protein was estimated to be 26.4 kDa in the presence of 1.5% 1-o-octyl-D -glucopyranoside (OGL), indicating that the native tungsten-binding protein is a heterodimeric protein. The amounts of tungsten bound to 1 mg of plasma membranes of A. ferrooxidans AP19-3 and the purified tungsten-binding protein at pH 3.0 were 191 and 1506 mug, respectively. In contrast, the amounts of tungsten bound to 1 mg of albumin, aldolase, catalase, chymotrypsinogen A, ferritin, and ferredoxin at pH 3.0 were 13.1, 18.6, 12.8, 16.6, 11.4, and 6.1 mug, respectively. Incubation of the tungsten-binding protein for 1 h with 10 mM Na(2)WO(4) plus 10 mM metal ion, such as NaVO(3), Na(2)MoO(4), CuSO(4), NiSO(4), MnSO(4), CoSO(4), or CdCl(2), did not markedly affect the amount of tungsten bound to the tungsten-binding protein, suggesting that the protein specifically binds tungsten.
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PMID:Existence of a tungsten-binding protein in Acidithiobacillus ferrooxidans AP19-3. 1623 46

Terminal erythropoiesis is accompanied by extreme demand for iron to ensure proper hemoglobinization. Thus, erythroblasts must modify the "standard" post-transcriptional feedback regulation, balancing expression of ferritin (Fer; iron storage) versus transferrin receptor (TfR1; iron uptake) via specific mRNA binding of iron regulatory proteins (IRPs). Although erythroid differentiation involves high levels of incoming iron, TfR1 mRNA stability must be sustained and Fer mRNA translation must not be activated because iron storage would counteract hemoglobinization. Furthermore, translation of the erythroid-specific form of aminolevulinic acid synthase (ALAS-E) mRNA, catalyzing the first step of heme biosynthesis and regulated similarly as Fer mRNA by IRPs, must be ensured. We addressed these questions using mass cultures of primary murine erythroid progenitors from fetal liver, either undergoing sustained proliferation or highly synchronous differentiation. We indeed observed strong inhibition of Fer mRNA translation and efficient ALAS-E mRNA translation in differentiating erythroblasts. Moreover, in contrast to self-renewing cells, TfR1 stability and IRP mRNA binding were no longer modulated by iron supply. These and additional data stemming from inhibition of heme synthesis with succinylacetone or from iron overload suggest that highly efficient utilization of iron in mitochondrial heme synthesis during normal erythropoiesis alters the regulation of iron metabolism via the IRE/IRP system.
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PMID:Remodeling the regulation of iron metabolism during erythroid differentiation to ensure efficient heme biosynthesis. 1642 95


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