Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q86TM3 (cage)
 29,987 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The reactions of nitriles (RCN) with arachno-4,6-C(2)B(7)H(12)(-) provide a general route to functionalized tricarbadecaboranyl anions, 6-R-nido-5,6,9-C(3)B(7)H(9)(-), R = C(6)H(5) (2(-)), NC(CH(2))(4) (4(-)), (p-BrC(6)H(4))(Me(3)SiO)CH (6(-)), C(14)H(11) (8(-)), and H(3)BNMe(2)(CH(2))(2) (10(-)). Further reaction of these anions with (eta(5)-C(5)H(5))Fe(CO)(2)I yields the functionalized ferratricarbadecaboranyl complexes 1-(eta(5)-C(5)H(5))-2-C(6)H(5)-closo-1,2,3,4-FeC(3)B(7)H(9) (3), 1-(eta(5)-C(5)H(5))-2-NC(CH(2))(4)-closo-1,2,3,4-FeC(3)B(7)H(9) (5), 1-(eta(5)-C(5)H(5))-2-[(p-BrC(6)H(4))(Me(3)SiO)CH]-closo-1,2,3,4-FeC(3)B(7)H(9) (7), 1-(eta(5)-C(5)H(5))-2-C(14)H(11)-closo-1,2,3,4-FeC(3)B(7)H(9) (9), and 1-(eta(5)-C(5)H(5))-2-H(3)BNMe(2)(CH(2))(2)-closo-1,2,3,4-FeC(3)B(7)H(9) (11). Reaction of 11 with DABCO (triethylenediamine) resulted in removal of the BH(3) group coordinated to the nitrogen of the side chain, giving 1-(eta(5)-C(5)H(5))-2-NMe(2)(CH(2))(2)-closo-1,2,3,4-FeC(3)B(7)H(9) (12). Crystallographic studies of complexes 3, 5, 7, 9, and 11 confirmed that these complexes are ferrocene analogues in which a formal Fe(2+) ion is sandwiched between the cyclopentadienyl and tricarbadecaboranyl monoanionic ligands. The metals are eta(6)-coordinated to the puckered six-membered face of the tricarbadecaboranyl cage, with the exopolyhedral substituents bonded to the low-coordinate carbon adjacent to the iron.
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PMID:Syntheses of functionalized ferratricarbadecaboranyl complexes. 1515 10

Anemia is extremely common in patients with cancer. Low hemoglobin levels are associated with diminished quality of life and possibly decreased overall survival. Successful treatment of anemia has undeniable benefits for patients, often yielding dramatic symptomatic improvement that can be very satisfying for clinicians to observe. This review focuses on evolving issues in the management of anemia in patients suffering from cancer. Topics addressed include new evidence-based guidelines concerning the use of epoetin alfa, the evolving role of darbepoetin alfa in cancer-associated anemia, the potential for concomitant iron supplementation to maximize response to erythropoietic agents, the unresolved question of whether erythropoietin use affects survival in cancer patients, new concerns about the risk of thromboembolism in cancer patients with higher hemoglobin levels who are receiving epoetin, and possible immunosuppressive effects of blood product transfusions that may have relevance to neoplasia progression.
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PMID:Management of anemia in patients with cancer. 1516 84

Ferritin, a major form of endogenous iron in food legumes such as soybeans, is a novel and natural alternative for iron supplementation strategies where effectiveness is limited by acceptability, cost, or undesirable side effects. A member of the nonheme iron group of dietary iron sources, ferritin is a complex with Fe3+ iron in a mineral (thousands of iron atoms inside a protein cage) protected from complexation. Ferritin illustrates the wide range of chemical and biological properties among nonheme iron sources. The wide range of nonheme iron receptors matched to the structure of the iron complexes that occurs in microorganisms may, by analogy, exist in humans. An understanding of the chemistry and biology of each type of dietary iron source (ferritin, heme, Fe2+ ion, etc.), and of the interactions dependent on food sources, genes, and gender, is required to design diets that will eradicate global iron deficiency in the twenty-first century.
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PMID:Iron, ferritin, and nutrition. 1518 24

The abiotic sorption and oxic degradation processes that control the fate of the explosive CL-20, Hexanitrohexaazaisowurtzitane, in the subsurface environment were investigated to determine the potential for vadose and groundwater contamination. Sorption of aqueous CL-20 is relatively small (K(d) = 0.02-3.83 cm3 g(-1) for 7 sediments and 12 minerals), which results in only slight retardation relative to water movement. Thus, CL-20 could move quickly through unsaturated and saturated sediments of comparable composition to groundwater, similar to the subsurface behavior of RDX. CL-20 sorption was mainly to mineral surfaces of the sediments, and the resulting isotherm was nonlinear. CL-20 abiotically degrades in oxic environments at slow rates (i.e., 10s to 100s of hours) with a wide variety of minerals, but at fast rates (i.e., minutes) in the presence of 2:1 phyllosilicate clays (hectorite, montmorillonite, nontronite), micas (biotite, illite), and specific oxides (MnO2 and the ferrous-ferric iron oxide magnetite). High concentrations of surface ferrous iron in a dithionite reduced sediment degraded CL-20 the fastest (half-life < 0.05 h), but 2:1 clays containing no structural or adsorbed ferrous iron (hectorite) could also quickly degrade CL-20 (half-life < 0.2 h). CL-20 degradation rates were slower in natural sediments (half-life 3-800 h) compared to minerals. Sediments with slow degradation rates and small sorption would exhibit the highest potential for deep subsurface migration. Products of CL-20 oxic degradation included three high molecular weight compounds and anions (nitrite and formate). The 2-3.5 moles of nitrite produced suggest CL-20 nitro-groups are degraded, and the amount of formate produced (0.2-1.2 moles) suggests the CL-20 cage structure is broken in some sediments. Identification of further degradation products and CL-20 mineralization rates is needed to fully assess the impact of these CL-20 transformation rates on the risk of CL-20 (and degradation product) subsurface movement.
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PMID:Sorption and oxic degradation of the explosive CL-20 during transport in subsurface sediments. 1521 2

The use of nonporphyrin complexes encapsulated in zeolites as catalysts for oxidation reactions has been improved in the past decades by the discovery of increasing numbers of nonheme monoxygenases. The zeolite lattice can change the oxidative chemistry of the metallocomplexes, resulting in a catalytic effect different from those observed in homogeneous reactions. We report the encapsulation of iron and copper metallocomplexes with the ligand (2-hydroxybenzyl)(2-methylpyridyl)amine, Hbpa, and iron complexes with the ligand N,N'-bis(2-hydroxybenzyl)-N,N'-bis(2-methylpyridyl) ethylenediamine, H(2)bbpen. The zeolite-encapsulated metallocomplexes were prepared by diffusion of the ligands through the pores of the zeolites, already exchanged with the respective metal. The syntheses were performed in methanol and toluene solutions. Elemental analysis of solids with the Hbpa ligand have indicated better complexation for synthesis in toluene, where 74% of the iron atoms were coordinated by the ligand, against 37% for the synthesis in methanol. For the immobilization with the H(2)bbpen ligand in toluene it was observed that 46% of the iron atoms are coordinated, showing that the diffusion of the small ligand Hbpa through the zeolite cage was facilitated. The EPR spectra of the solids show signals at g = 2.0, which was attributed to an Fe-Fe interaction from the noncoordinated atoms, and g = 4.3 attributed to iron (III) in a rhombic geometry.
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PMID:Encapsulation of Fe(III) and Cu(II) complexes in NaY zeolite. 1527 50

Complexation of the highly branched, pentadecadentate chelating ligand cis,cis-1,3,5-cyclohexanetriamine-N,N,N',N',N",N"-hexaacetic acid (H(6)L) with iron(III) and sodium cations in the presence of carbonate anions leads to the formation of an [Fe6L2] cluster comprising an [Fe6] cage linked by 12 exo-coordinated sodium cations to form an extended 3D array.
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PMID:Pentadecadentate chelating ligands as building blocks for a [Fe6] cage with 12 exo-coordinated sodium cations. 1553 71

Ferritins are spherical, cage-like proteins with nanocavities formed by multiple polypeptide subunits (four-helix bundles) that manage iron/oxygen chemistry. Catalytic coupling yields diferric oxo/hydroxo complexes at ferroxidase sites in maxi-ferritin subunits (24 subunits, 480 kDa; plants, animals, microorganisms). Oxidation occurs at the cavity surface of mini-ferritins/Dps proteins (12 subunits, 240 kDa; bacteria). Oxidation products are concentrated as minerals in the nanocavity for iron-protein cofactor synthesis (maxi-ferritins) or DNA protection (mini-ferritins). The protein cage and nanocavity characterize all ferritins, although amino acid sequences diverge, especially in bacteria. Catalytic oxidation/di-iron coupling in the protein cage (maxi-ferritins, 480 kDa; plants, bacteria and animal cell-specific isoforms) or on the cavity surface (mini-ferritins/Dps proteins, 280 kDa; bacteria) initiates mineralization. Gated pores (eight or four), symmetrically arranged, control iron flow. The multiple ferritin functions combine pore, channel, and catalytic functions in compact protein structures required for life and disease response.
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PMID:Ferritins: dynamic management of biological iron and oxygen chemistry. 1576 35

This paper provides a critical review of the numerous and various biological functions so far attributed to neuromelanin and an attempt to provide a unified theory based on the peculiar physical and chemical properties of the black particle (the neuromelanin cage). It is stressed that neuromelanin is not homogeneous, as is commonly accepted, but is made up of different substrate specific black pigments formed by the oxidation of o.diphenols or other oxygenated precursors (substantia nigra melanin, locus coeruleus melanin, retinal pigmented epithelium or ocular melanin, inner-ear melanin, and so on). Ocular melanin is believed to protect the eye by trapping metals and free radicals. The paper shows that this unconfirmed mechanism is a rather fortuitous irreversible molecular accident, which at times may prove itself deleterious. Albinism often leads to deafness in animals, indicating a genetic correlation. These two conditions appear to be correlated at a molecular level to eye/ear pigmentation and suggest verifying this hypothesis in normal and albino human individuals. Skin and ocular melanin are chemically different. However, they are both involved in light absorption/dissipation. The black particle structure (melanin cage) is believed to be fundamental to this process because there is a common bioelectric mechanism. The latter is worth of further investigation. It is also proposed checking how ocular melanin dissipates the excessive absorbed light (as heat or as current?). It has been claimed that inner-ear melanin mutes acoustic waves. This paper suggests investigating the underlying mechanism and also studying whether this pigment is bio-electrically involved in audiology. According to numerous authors, substantia nigra melanin is only biological garbage. This view is rejected, and it is stressed that intracellular melanogenesis is a fundamental and genetically controlled physiological process. It has been repeatedly claimed that the binding of iron, heavy metals, free radicals and harmful chemicals by substantia nigra melanin is fundamental to body detoxification/protection. Presumably, such irreversible and generic binding mechanisms have no physiological foundation; it is suggested the alternative that, substantia nigra melanin acts as semiconductor, transmitting and modulating nervous impulses, in a reversible way. In fact, substantia nigra melanin is absent or significantly scarce in two conditions of life in which the coordination of movement is either inefficient (newborn babies) or strongly compromised (Parkinson). To check this assumption, further investigation of nucleus caudatus, putamen, globus pallidus, substantia nigra pars compacta and reticulata, nucleus hypothalamicus is recommended.
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PMID:A critical review of the function of neuromelanin and an attempt to provide a unified theory. 1594 1

Evolution of an oxygenic atmosphere required primordial life to accommodate the toxicity associated with reactive oxygen species. We have characterized an archaeal antioxidant from the hyperthermophilic acidophile Sulfolobus solfataricus. The amino acid sequence of this approximately 22-kDa protein shares little sequence similarity with proteins with known function. However, the protein shares high sequence similarity with hypothetical proteins in other archaeal and bacterial genomes. Nine of these hypothetical proteins form a monophyletic cluster within the broad superfamily of ferritin-like diiron-carboxylate proteins. Higher order structural predictions and image reconstructions indicate that the S. solfataricus protein is structurally related to a class of DNA-binding protein from starved cells (Dps). The recombinant protein self assembles into a hollow dodecameric protein cage having tetrahedral symmetry (SsDps). The outer shell diameter is approximately 10 nm, and the interior diameter is approximately 5 nm. Dps proteins have been shown to protect nucleic acids by physically shielding DNA against oxidative damage and by consuming constituents involved in Fenton chemistry. In vitro, the assembled archaeal protein efficiently uses H2O2 to oxidize Fe(II) to Fe(III) and stores the oxide as a mineral core on the interior surface of the protein cage. The ssdps gene is up-regulated in S. solfataricus cultures grown in iron-depleted media and upon H2O2 stress, but is not induced by other stresses. SsDps-mediated reduction of hydrogen peroxide and possible DNA-binding capabilities of this archaeal Dps protein are mechanisms by which S. solfataricus mitigates oxidative damage.
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PMID:An archaeal antioxidant: characterization of a Dps-like protein from Sulfolobus solfataricus. 1602 30

The diameter of single walled carbon nanotubes (SWNTs) determines the electronic properties of the nanotube. The diameter of carbon nanotubes is dictated by the diameter of the catalyst particle. Here we describe the use of iron nanoparticles synthesized within the Dps protein cage as catalysts for the growth of single-walled carbon nanotubes. The discrete iron particles synthesized within the Dps protein cages when used as catalyst particles gives rise to single-walled carbon nanotubes with a limited diameter distribution.
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PMID:Constrained iron catalysts for single-walled carbon nanotube growth. 1611 58


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