scholarly journals Reductive Mobilization of Iron from Intact Ferritin: Mechanisms and Physiological Implication

2018 ◽  
Vol 11 (4) ◽  
pp. 120 ◽  
Author(s):  
Fadi Bou-Abdallah ◽  
John Paliakkara ◽  
Galina Melman ◽  
Artem Melman
Keyword(s):  
Protein Structures ◽  
Reducing Agents ◽  
Iron Core ◽  
Ferrous Ions ◽  
Major Pathway ◽  
Iron Mobilization ◽  
Iron Mineral ◽  
Mineral Core

Ferritins are highly conserved supramolecular protein nanostructures composed of two different subunit types, H (heavy) and L (light). The two subunits co-assemble into a 24-subunit heteropolymer, with tissue specific distributions, to form shell-like protein structures within which thousands of iron atoms are stored as a soluble inorganic ferric iron core. In-vitro (or in cell free systems), the mechanisms of iron(II) oxidation and formation of the mineral core have been extensively investigated, although it is still unclear how iron is loaded into the protein in-vivo. In contrast, there is a wide spread belief that the major pathway of iron mobilization from ferritin involves a lysosomal proteolytic degradation of ferritin, and the dissolution of the iron mineral core. However, it is still unclear whether other auxiliary iron mobilization mechanisms, involving physiological reducing agents and/or cellular reductases, contribute to the release of iron from ferritin. In vitro iron mobilization from ferritin can be achieved using different reducing agents, capable of easily reducing the ferritin iron core, to produce soluble ferrous ions that are subsequently chelated by strong iron(II)-chelating agents. Here, we review our current understanding of iron mobilization from ferritin by various reducing agents, and report on recent results from our laboratory, in support of a mechanism that involves a one-electron transfer through the protein shell to the iron mineral core. The physiological significance of the iron reductive mobilization from ferritin by the non-enzymatic FMN/NAD(P)H system is also discussed.

Antioxidant Activity, Phenolic Content and Hematoprotective Effects of Cleome arabica Polyphenolic Leaf Extract

2019 ◽  
Author(s):  
C. Tigrine ◽  
A. Kameli
Keyword(s):  
Antioxidant Activity ◽  
Biological Effects ◽  
Reducing Power ◽  
Hematological Toxicity ◽  
Protective Effects ◽  
Ferrous Ions ◽  
Polyphenolic Extract ◽  
Cleome Arabica

In this study a polyphenolic extract from Cleome arabica leaves (CALE) was investigated for its antioxidant activity in vitro using DPPH•, metal chelating and reducing power methods and for its protective effects against AraC-induced hematological toxicity in vivo using Balb C mice. Results indicated that CALE exhibited a strong and dose-dependent scavenging activity against the DPPH• free radical (IC50 = 4.88 μg/ml) and a high reducing power activity (EC50 = 4.85 μg/ml). Furthermore, it showed a good chelating effects against ferrous ions (IC50 = 377.75 μg/ml). The analysis of blood showed that subcutaneous injection of AraC (50 mg/kg) to mice during three consecutive days caused a significant myelosupression (P < 0.05). The combination of CALE and AraC protected blood cells from a veritable toxicity. Where, the number of the red cells, the amount of hemoglobin and the percentage of the hematocrite were significantly high. On the other hand, AraC cause an elevation of body temperature (39 °C) in mice. However, the temperature of the group treated with CALE and AraC remained normal and did not exceed 37.5 °C. The observed biological effects of CALE, in vitro as well as in vivo, could be due to the high polyphenol and flavonoid contents. In addition, the antioxidant activity of CALE suggested to be responsible for its hematoprotective effect.

scholarly journals Breakdown of Filamentous Myofibrils by the UPS–Step by Step

Biomolecules ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 110
Author(s):  
Dina Aweida ◽  
Shenhav Cohen
Keyword(s):  
Protein Quality ◽  
Protein Structures ◽  
Ubiquitin Proteasome System ◽  
Surface Proteins ◽  
Catalytic Core ◽  
Complex Protein ◽  
Ubiquitin Proteasome ◽  
Aaa Atpases

Protein degradation maintains cellular integrity by regulating virtually all biological processes, whereas impaired proteolysis perturbs protein quality control, and often leads to human disease. Two major proteolytic systems are responsible for protein breakdown in all cells: autophagy, which facilitates the loss of organelles, protein aggregates, and cell surface proteins; and the ubiquitin-proteasome system (UPS), which promotes degradation of mainly soluble proteins. Recent findings indicate that more complex protein structures, such as filamentous assemblies, which are not accessible to the catalytic core of the proteasome in vitro, can be efficiently degraded by this proteolytic machinery in systemic catabolic states in vivo. Mechanisms that loosen the filamentous structure seem to be activated first, hence increasing the accessibility of protein constituents to the UPS. In this review, we will discuss the mechanisms underlying the disassembly and loss of the intricate insoluble filamentous myofibrils, which are responsible for muscle contraction, and whose degradation by the UPS causes weakness and disability in aging and disease. Several lines of evidence indicate that myofibril breakdown occurs in a strictly ordered and controlled manner, and the function of AAA-ATPases is crucial for their disassembly and loss.

scholarly journals Characterization of Iron Core–Gold Shell Nanoparticles for Anti-Cancer Treatments: Chemical and Structural Transformations During Storage and Use

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2572 ◽  
Author(s):  
Ya-Na Wu ◽  
Dar-Bin Shieh ◽  
Li-Xing Yang ◽  
Hwo-Shuenn Sheu ◽  
Rongkun Thordarson ◽  
...  
Keyword(s):  
Au Nanoparticles ◽  
Iron Core ◽  
Cancer Treatments ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Anti Cancer ◽  
One Year ◽  
Means Of Transmission

Finding a cancer-selective drug that avoids damaging healthy cells and organs is a holy grail in medical research. In our previous studies, gold-coated iron (Fe@Au) nanoparticles showed cancer selective anti-cancer properties in vitro and in vivo but were found to gradually lose that activity with storage or "ageing.” To determine the reasons for this diminished anti-cancer activity, we examined Fe@Au nanoparticles at different preparation and storage stages by means of transmission electron microscopy combined with and energy-dispersive X-ray spectroscopy, along with X-ray diffraction analysis and cell viability tests. We found that dried and reconstituted Fe@Au nanoparticles, or Fe@Au nanoparticles within cells, decompose into irregular fragments of γ-F2O3 and agglomerated gold clumps. These changes cause the loss of the particles’ anti-cancer effects. However, we identified that the anti-cancer properties of Fe@Au nanoparticles can be well preserved under argon or, better still, liquid nitrogen storage for six months and at least one year, respectively.

scholarly journals Evaluation of The Antioxidant, Antidiabetic and Immunomodulatory Activity of Cydonia oblonga Fruit Extract

2021 ◽  
Vol 20 (3) ◽  
Author(s):  
Fatma Zahra Sakhri ◽  
Sakina Zerizer ◽  
Chawki Bensouici
Keyword(s):  
Free Radicals ◽  
Cation Radical ◽  
Antidiabetic Activity ◽  
Immunomodulatory Activity ◽  
Ferrous Ions ◽  
Cydonia Oblonga ◽  
Innate Defense ◽  
Hydroethanolic Extract

Dietary natural antioxidant consumption can protect the human body from several diseases induced by free radicals. The aim of this study was to evaluate the antioxidant, antidiabetic and immunomodulatory properties of Cydonia oblonga fruit. For this; hydroethanolic extract of Cydonia oblonga fruit (HECO) was examined for antioxidant activity using DPPH free radical sc avenging, ABTS cation radical decolorization, Cupric reducing antioxidant capacity (CUPRAC), and Metal Chelating on ferrous ions activities. The inhibitory activity of the extract against α-glucosidase enzyme was also investigated. HECO was tested in vivo for the immunomodulatory activity on non-specific immunity by the carbon clearance test. The content of the nonenzymatic antioxidant reduced glutathione (GSH) in liver tissue of used mice was estimated. in vitro studies revealed that the HECO has an inhibitory concentration (IC50) value of 249.26 ± 3.75μg/mL, 117.34 ± 1.41 μg/ml for DPPH and ABTS scavenging activity respectively. As well as the ability to reduce cupric (167.17 ± 1.15μg/mL) and iron (Fe) (417.98 ± 48.82μg/mL). The extract showed antidiabetic activity as evidenced by its capacity to inhibit the α-glucosidase enzyme (IC50: 326.48 ± 18.56 µg/mL) near the acarbose (IC50: 275.98 ± 1.57 µg/mL) used as a positive control. In addition, our results showed that HECO at the concentration of 50 and 100 mg/kg significantly increased the clearance rate of carbon from the bloodstream concomitant with increased liberation of GSH from liver cells. This study demonstrates that HECO is effective in scavenging free radicals and can serve as potent antioxidants that provide potential treatment and prevention for diabetes with benefits on the innate defense system. Keywords: Antidiabetic, Antioxidant, Cydonia oblonga, Hydroethanolic extract, Phagocytic activity

A Brief History of the Discovery of Amelogenin Nanoribbons In Vitro and In Vivo

2021 ◽  
pp. 002203452110434
Author(s):  
Y. Bai ◽  
J. Bonde ◽  
K.M.M. Carneiro ◽  
Y. Zhang ◽  
W. Li ◽  
...  
Keyword(s):  
Recombinant Proteins ◽  
Protein Structures ◽  
Historical Review ◽  
Limited Information ◽  
Transmission Electron Microscopy Analysis ◽  
Electron Microscopy Analysis ◽  
History Of ◽  
The 1960S

Without evidence for an organic framework, biological and biochemical processes observed during amelogenesis provided limited information on how extracellular matrix proteins control the development of the complex fibrous architecture of human enamel. Over a decade ago, amelogenin nanoribbons were first observed from recombinant proteins during in vitro mineralization experiments in our laboratory. In enamel from mice lacking the enzyme kallikrein 4 (KLK4), we later uncovered ribbon-like protein structures that matched the morphology, width, and thickness of the nanoribbons assembled by recombinant proteins. Interestingly, similar structures had already been described since the 1960s, when enamel sections from various mammals were demineralized and stained for transmission electron microscopy analysis. However, at that time, researchers were not aware of the ability of amelogenin to form nanoribbons and instead associated the filamentous nanostructures with possible imprints of mineral ribbons in the gel-like matrix of developing enamel. Further evidence for the significance of amelogenin nanoribbons for enamel development was stipulated when recent mineralization experiments succeeded in templating and orienting the growth of apatite ribbons along the protein nanoribbon framework. This article provides a brief historical review of the discovery of amelogenin nanoribbons in our laboratory in the context of reports by others on similar structures in the developing enamel matrix.

scholarly journals Modification of Cysteine Residues In Vitro and In Vivo Affects the Immunogenicity and Antigenicity of Major Histocompatibility Complex Class I–restricted Viral Determinants

1999 ◽  
Vol 189 (11) ◽  
pp. 1757-1764 ◽  
Author(s):  
Weisan Chen ◽  
Jonathan W. Yewdell ◽  
Rodney L. Levine ◽  
Jack R. Bennink
Keyword(s):  
Influenza Virus ◽  
Posttranslational Modifications ◽  
Synthetic Peptides ◽  
Influenza Virus Infection ◽  
Lymphocytic Choriomeningitis ◽  
Reducing Agents ◽  
Cysteine Residues ◽  
T Cell Lines

In studying the subdominant status of two cysteine-containing influenza virus nuclear protein (NP) determinants (NP39–47 and NP218–226) restricted by H-2Kd, we found that the antigenicity of synthetic peptides was enhanced 10–100-fold by treatment with reducing agents, despite the fact that the affinity for Kd was not enhanced. Reducing agents also markedly enhanced the immunogenicity of cysteine-containing peptides, as measured by propagation of long-term T cell lines in vitro. Similar enhancing effects were obtained by substituting cysteine with alanine or serine in the synthetic peptides, demonstrating that sulfhydryl modification of cysteine is responsible for the impaired antigenicity and immunogenicity of NP39–47 and NP218–226. We found similar effects for two widely studied, cysteine-containing peptides from lymphocytic choriomeningitis virus. The major modifications of cysteine-containing synthetic peptides are cysteinylation and dimerization occurring through cysteine residues. We demonstrate that both of these modifications occur in cells synthesizing a cytosolic NP218–226 minigene product and, further, that T cells specific for cysteinylated NP218–226 are induced by influenza virus infection in mice, demonstrating that this modification occurs in vivo. These findings demonstrate that posttranslational modifications affect the immunogenicity and antigenicity of cysteine-containing viral peptides and that this must be considered in studying the status of such peptides in immunodominance hierarchies.

scholarly journals Natural Products for Anti-Cancer Progress: The Impact of Artificial Intelligence

Proceedings ◽  
2019 ◽  
Vol 40 (1) ◽  
pp. 37
Author(s):  
Buyukbingol
Keyword(s):  
Artificial Intelligence ◽  
Treatment Success ◽  
Protein Structures ◽  
Genetic Profile ◽  
Plant Origin ◽  
Drug Molecules ◽  
The Impact ◽  
Plant Sources

Finding for more effective anticancer drugs on almost different types of cancer, a huge number of molecules is still under evaluation and barely many more than 100,000 compounds have been tested with researchers and several institutions since recent decades. The fact that plant-derived molecules are treated at various levels against cancer is based on a very long history. This has enabled many molecules derived from plant sources to be used in cancer treatment. With the introduction of artificial intelligence, studies on the discovery of new molecules that may be effective in the etiology of various diseases have gained weight as in every field. Artificial intelligence learns the relationship between molecular structure and biological components in certain mathematical algorithms with the obtained in vitro and in vivo values and helps to create new molecular patterns as a result of certain validations. In fact, the artificial intelligence, is now able to develop novel algorithms over the initially defined and further realization might proceed new designs with advanced programming by self-settings new routes through the improvement of desired targets. The introduction of the genetic profile and consequently the discovery of new drug molecules will be one of the most important fields of study of the future. Molecules to be obtained from plant sources will also have very important roles in this direction. Drug therapy for patients with the same disease but with a different genetic profile does not give the same treatment success in every patient. The reason for this is that due to the different mutations in DNA, the protein structures encoded by the genes show differences and the interaction pattern of molecules on the proteins responsible for diseases, could be different. Therefore, for each patient, due to the mutation, diverse molecules that can interact with mutated proteins should be required. This issue is becoming increasingly important all over the world, especially under the name of precision medicine and in the form of personalized drug administration, and demonstrates the importance of drug treatment depending on the individual's genetic profile. It is then useful to treat anticancer molecules of plant origin in this direction. For this purpose, gene rearrangements and gene editing procedures can be applied in plants by using CRISPR technology to improve several factors through leading to design and develop new plant origin molecules for the intended purpose with the assistance of artificial intelligence algorithms.

scholarly journals Combined structural, biochemical and cellular evidence demonstrates that both FGDF motifs in alphavirus nsP3 are required for efficient replication

Open Biology ◽  
2016 ◽  
Vol 6 (7) ◽  
pp. 160078 ◽  
Author(s):  
Tim Schulte ◽  
Lifeng Liu ◽  
Marc D. Panas ◽  
Bastian Thaa ◽  
Nicole Dickson ◽  
...  
Keyword(s):  
Viral Replication ◽  
Semliki Forest Virus ◽  
Protein Structures ◽  
Growth Curves ◽  
Structural Protein ◽  
Binding Studies ◽  
Efficient Replication ◽  
Hierarchical Interaction

Recent findings have highlighted the role of the Old World alphavirus non-structural protein 3 (nsP3) as a host defence modulator that functions by disrupting stress granules, subcellular phase-dense RNA/protein structures formed upon environmental stress. This disruption mechanism was largely explained through nsP3-mediated recruitment of the host G3BP protein via two tandem FGDF motifs. Here, we present the 1.9 Å resolution crystal structure of the NTF2-like domain of G3BP-1 in complex with a 25-residue peptide derived from Semliki Forest virus nsP3 (nsP3-25). The structure reveals a poly-complex of G3BP-1 dimers interconnected through the FGDF motifs in nsP3-25. Although in vitro and in vivo binding studies revealed a hierarchical interaction of the two FGDF motifs with G3BP-1, viral growth curves clearly demonstrated that two intact FGDF motifs are required for efficient viral replication. Chikungunya virus nsP3 also binds G3BP dimers via a hierarchical interaction, which was found to be critical for viral replication. These results highlight a conserved molecular mechanism in host cell modulation.

scholarly journals Interplay between DsbA1, DsbA2 and C8J_1298 Periplasmic Oxidoreductases of Campylobacter jejuni and Their Impact on Bacterial Physiology and Pathogenesis

2021 ◽  
Vol 22 (24) ◽  
pp. 13451
Author(s):  
Anna M. Banaś ◽  
Katarzyna M. Bocian-Ostrzycka ◽  
Stanisław Dunin-Horkawicz ◽  
Jan Ludwiczak ◽  
Piotr Wilk ◽  
...  
Keyword(s):  
Campylobacter Jejuni ◽  
Protein Structures ◽  
Essential Elements ◽  
Bacterial Physiology ◽  
Bacterial Proteins ◽  
In Vivo Experiments ◽  
Redox Partner ◽  
Periplasmic Transport

The bacterial proteins of the Dsb family catalyze the formation of disulfide bridges between cysteine residues that stabilize protein structures and ensure their proper functioning. Here, we report the detailed analysis of the Dsb pathway of Campylobacter jejuni. The oxidizing Dsb system of this pathogen is unique because it consists of two monomeric DsbAs (DsbA1 and DsbA2) and one dimeric bifunctional protein (C8J_1298). Previously, we showed that DsbA1 and C8J_1298 are redundant. Here, we unraveled the interaction between the two monomeric DsbAs by in vitro and in vivo experiments and by solving their structures and found that both monomeric DsbAs are dispensable proteins. Their structures confirmed that they are homologs of EcDsbL. The slight differences seen in the surface charge of the proteins do not affect the interaction with their redox partner. Comparative proteomics showed that several respiratory proteins, as well as periplasmic transport proteins, are targets of the Dsb system. Some of these, both donors and electron acceptors, are essential elements of the C. jejuni respiratory process under oxygen-limiting conditions in the host intestine. The data presented provide detailed information on the function of the C. jejuni Dsb system, identifying it as a potential target for novel antibacterial molecules.

Transmission electron microscope studies of a piliated strain of Haemophilus influenzae B

1983 ◽  
Vol 41 ◽  
pp. 808-809
Author(s):  
Doris Palmer Booth
Keyword(s):  
Haemophilus Influenzae ◽  
Polyacrylamide Gel Electrophoresis ◽  
Protein Structures ◽  
Sodium Dodecyl ◽  
Apparent Molecular Weight ◽  
Haemophilus Influenzae Type ◽  
Transmission Electron ◽  
Neisseria Gonorrhea

The role of pili as a mucosal attachment factor that enhances colonization and pathogenicity is well known in Escherichia coli, Neisseria gonorrhea, Streptococcus pyrogenes and Proteus mirabilis. Although Haemophilus influenzae type b (Hib) causes serious infections in children such as meningitis, pneumonia, septic arthritis and epiglottitis, very little information is available about Hib piliation and subsequent adhesion and colonization in vivo. Hib piliation was recently correlated with hemagglutination and adherence (in vitro) to human buccal epithelial cells by Pichichero, et al.Pili are protein structures which extend from the outer membrane of Hib. Purified pili have an apparent molecular weight of 23,000 daltons by Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and aggregate laterally as well as end on end to form thick filamentous structures. Although pili seem to enhance attachment to respiratory mucosa (a significant foothold during the invasion of healthy tissue) the relative pathogenicity of piliated and non-piliated Hib is yet to be determined.

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