Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Small ribosomal subunits from the prokaryote Escherichia coli and the eukaryote Thermomyces lanuginosus were imaged electron spectroscopically, and single particle analysis used to yield three-dimensional reconstructions of the net phosphorus distribution representing the nucleic acid (RNA) backbone. This direct approach showed both ribosomal RNAs to have a three domain structure and other characteristic morphological features. The eukaryotic small ribosomal subunit had a prominent bill present in the head domain, while the prokaryotic subunit had a small vestigial bill. Both ribosomal subunits contained a thick 'collar' central domain which correlates to the site of the evolutionarily conserved ribosomal RNA core, and the location of the majority of ribosomal RNA bases that have been implicated in translation. The reconstruction of the prokaryotic subunit had a prominent protrusion extending from the collar, forming a channel approximately 1.5 nm wide and potentially representing a 'bridge' to the large subunit in the intact monosome. The basal domain of the prokaryotic ribosomal subunit was protein free. In this region of the eukaryotic subunit, there were two basal lobes composed of ribosomal RNA, consistent with previous hypotheses that this is a site for the 'non-conserved core' ribosomal RNA.
Mol Cell Biochem 1995 Jul 19
PMID:Structures of small subunit ribosomal RNAs in situ from Escherichia coli and Thermomyces lanuginosus. 859 21

Ab initio molecular orbital investigations of the [2+2] electrocyclization of 3-substituted pentadienyl cations, where the substituents are BH2, AlH2, OH, SH, NH2, PH2, or H, show significant substituent effects on the ground state conformations, transition structures, and energies of activation. Locating the transition structure for the cyclization of the PH2-substituted system was particularly troublesome due to the tendency of the phosphorus group to undergo inversion. The AVS Chemistry Viewer, a data flow environment-based application for the analysis, visualization, and animation of molecular modeling results, proved useful in mapping the potential energy hypersurface and understanding the transition structures for this system.
J Mol Graph 1995 Oct
PMID:Identification of multiple transition structures on the potential energy hypersurface for [2+2] electrocyclization of the pentadienyl cation bearing a phosphorus in the 3-position. 860 56

Effect of feeding 0.5% curcumin diet or 1% cholesterol diet was examined in albino rats rendered diabetic with streptozotocin injection. Diabetic rats maintained on curcumin diet for 8 weeks excreted comparatively less amounts of albumin, urea, creatinine and inorganic phosphorus. Urinary excretion of the electrolytes sodium and potassium were also significantly lowered under curcumin treatment. Dietary curcumin also partially reversed the abnormalities in plasma albumin, urea, creatine and inorganic phosphorus in diabetic animals. On the other hand, glucose excretion or the fasting sugar level was unaffected by dietary curcumin and so also the body weights were not improved to any significant extent. Diabetic rats fed curcumin diet had a lowered relative liver weight at the end of the study compared to other diabetic groups. Diabetic rats fed a curcumin diet also showed lowered lipid peroxidation in plasma and urine when compared to other diabetic groups. The extent of lipid peroxidation on the other hand, was still higher in cholesterol fed diabetic groups compared to diabetic rats fed with control diet. Thus, the study reveals that curcumin feeding improves the metabolic status in diabetic conditions, despite no effect on hyperglycemic status or the body weights. The mechanism by which curcumin improves this situation is probably by virtue of its hypocholesterolemic influence, antioxidant nature and free radical scavenging property.
Mol Cell Biochem 1995 Nov 08
PMID:Influence of dietary curcumin and cholesterol on the progression of experimentally induced diabetes in albino rat. 860 7

We previously demonstrated that feeding rats the Steenbock and Black rickets-inducing diet produces remarkable changes in the metabolic pattern of intestinal mucosa, kidney, liver, cerebral cortex and heart. We have now determined the levels of calcium, phosphorus and citrate in cerebral cortex and the activity of some enzymes in synaptosomes and cerebral cortex mitochondria of three rat groups: control (Group A), fed a vitamin D-deficient diet (Group B), fed a vitamin D-deficient diet and treated with 1,25-dihydroxyvitamin D3 (Group C). While calcium content increased in Groups B and C, phosphorus concentration increased only in Group C and citrate in Group B in comparison with control. The increase in acetylcholinesterase and citrate synthase registered in Group B was restored to control values by 1,25-dihydroxyvitamin D3 treatment, while, neither the decrease in cytochrome c oxidase, nor the increase in glucose-6-phosphate dehydrogenase, acid phosphatase and NADP+(-)isocitrate dehydrogenase observed in Group B were corrected by 1,25-dihydroxyvitamin D3 supply. Acyl phosphatase showed a remarkable increase in consequence of 1,25-dihydroxyvitamin D3 administration.
Biochem Mol Biol Int 1995 Nov
PMID:Vitamin D--related modification of enzyme activities in synaptosomes and mitochondria isolated from rat cerebral cortex. 862 85

The aim of this study was to highlight a possible new non-aluminum phosphate-binder to limit hyperphosphatemia in patients with renal failure. Lanthanum chloride hydrate was evaluated as a dietary phosphate binder in rats. Aluminum chloride hexahydrate was evaluated as a reference. Animals were divided in five groups (6 animals per group): 1 control group (C), 2 aluminum groups (Al1 and Al2), receiving different doses of aluminum chloride hexahydrate and 2 lanthanum groups (La1 and La2), receiving different doses of lanthanum chloride hydrate. During the treatment, urine and stools were collected. At the end of the treatment animals were sacrificed and plasma and different organs were collected (liver, spleen, kidneys, brain and femur). To highlight the possible transfer of lanthanum in rat tissues, a long-term (100 days) study was carried with a high dose. At the end of the treatment, lanthanum determinations were carried out on several tissues (liver, spleen, kidneys, brain, femur and lungs). Determinations of phosphorus and calcium levels in plasma indicated that lanthanum chloride hydrate showed as good results as aluminum chloride hexahydrate. Lanthanum chloride hydrate significantly (p < 0.01) reduced the bone phosphorus burden. Decreases of urinary excretion and increases in fecal excretion of phosphorus indicated a severe phosphorus depletion in all treatments (Al and La). Unfortunately, in the long-term study, lanthanum traces could only be determined in the different tissues but not in plasma. However, in comparison with the equivalent aluminum treatment, the transfer of lanthanum was less important than aluminum transfer. Consequently, lanthanum could provide a possible alternative to aluminum.
Res Commun Mol Pathol Pharmacol 1995 Sep
PMID:A possible non-aluminum oral phosphate binder? A comparative study on dietary phosphorus absorption. 868 Aug 6

Purple acid phosphatase is a widely distributed non-specific phosphomonoesterase. X-ray structures of the dimeric 111-kDa Fe(III)-Zn(II) kidney bean purple acid phosphatase (kbPAP) complexed with phosphate, the product of the reaction, and with tungstate, a strong inhibitor of the phosphatase activity, were determined at 2.7 and 3.0 angstroms resolution, respectively. Furthermore the resolution of the unligated enzyme, recently solved at 2.9 angstroms could be extended to 2.65 angstroms with completely new data. The binding of both oxoanions is not accompanied by larger conformational changes in the enzyme structure. Small movements with a maximal coordinate shift of 1 angstroms are only observed for the active site residues His295 and His296. In the inhibitor complex as well as in the product complex, the oxoanion binds in a bidentate bridging mode to the two metal ions, replacing two of the presumed solvent ligands present in the unligated enzyme form. As also proposed for the unligated structure a bridging hydroxide ion completes the coordination spheres of both metal ions to octahedral arrangements. All three structures reported herein support a mechanism of phosphate ester hydrolysis involving interaction of the substrate with Zn(II) followed by a nucleophilic attack on the phosphorus by an Fe(III)-coordinated hydroxide ion. The negative charge evolving at the pentacoordinated transition state is probably stabilized by interactions with the divalent zinc and the imidazole groups of His202, His295, and His296, the latter protonating the leaving alcohol group.
J Mol Biol 1996 Jun 21
PMID:Mechanism of Fe(III)-Zn(II) purple acid phosphatase based on crystal structures. 868 79

The aim of this study was to study a possible new non-aluminum phosphate-binder to limit hyperphosphatemia in patients with renal failure. Zirconyl chloride octahydrate was evaluated as a dietary phosphate binder in rats. Aluminum chloride hexahydrate was used as a reference. Animals were divided into six groups (6 animals per group): One - control group (C), two - aluminum groups (Al1 and Al2) and three - zirconium groups (Zr1, Zr2 and Zr3) receiving different doses of zirconyl chloride octahydrate. Urines were collected during the experimental period. At the end of the treatment, the animals were sacrified and plasma and different organs were collected (liver, spleen, kidneys, brain and femur). Determination of phosphorus and calcium levels in plasma indicated that zirconyl chloride octahydrate yielded as good results as aluminum chloride hexahydrate did. Zirconyl chloride octahydrate significantly (p<0.01) reduced bone phosphorus burden. Urinary excretion of phosphorus indicated a severe phosphorus depletion in all treatments. Not even traces of zirconium could be determined in the different tissues, in urines or in plasma. Consequently, it is important to carry out experiments with zirconium compounds in order to develop non-aluminum-containing phosphate binders.
Res Commun Mol Pathol Pharmacol 1995 Dec
PMID:Reduction of dietary phosphorus absorption by oral phoshorus binders. 874 85

The role of the lysosome during the intracellular concentration of diverse mineral elements has been evidenced by the electron probe X-ray microanalysis (EPMA). This highly sensitive technique allows an in situ chemical analysis of any chemical element with an atomic number greater than 11, present in ultra-thin tissue sections. Therefore, it has been demonstrated by using this EPMA that 21 out of the 92 elements of the periodic table, once injected in a soluble form, were selectively concentrated within lysosomes of several types of mammalian cells. Amongst these 21 elements, 15 are concentrated and precipitated in an insoluble from in association with phosphorus whereas the other 6 are precipitated in association with sulphur. Amongst the 15 elements which precipitate with phosphorus in lysosomes, there are: 3 group IIIB elements of the periodic system, (aluminium, gallium and indium); the rare-earth elements (cerium, gadolinium, lanthanum, thulium and samarium); 2 group IVA elements (hafnium and zirconium), two actinides (uranium and thorium) and elements such as chromium and niobium. The 6 elements which precipitate with sulphur comprise the 3 group VIII elements of the classification (nickel, palladium, platinum) and the 3 group IB elements (copper, silver and gold). The mechanisms responsible for this selective concentration involve enzymatic processes and predominantly acid phosphatases for elements precipitating as phosphates and arylsulfatases for elements precipitating with sulphur.
Cell Mol Biol (Noisy-le-grand) 1996 May
PMID:The role of lysosomes in the selective concentration of mineral elements. A microanalytical study. 879 93

We report the analysis of the solution structure of the DNA duplex d(CTTCGAAG)2 compared to that of d(CATCGATG)2, the two oligonucleotides being related by the permutation of residues 2 and 7. An earlier study has demonstrated the malleability of CpG in the tetrad TCGA of d(CATCGATG)2 [Lefebvre et al. (1995) Biochemistry 34, 12019-12028]. Conformations of d(CTTCGAAG)2 were evaluated by (a) two-dimensional NMR, including proton and phosphorus experiments, (b) adiabatic mapping of the conformational space, (c) restrained molecular mechanics undertaken with sugar phase angle, epsilon-zeta difference angle, and NOE distances as input, and (d) back-calculation-refinement against NOE spectra at various mixing times. d(CTTCGAAG)2 like d(CATCGATG)2 exhibits a B-DNA conformation. However, significant differences are noted between the two oligonucleotides, extending up to the central CpG step, although this step resides in the same TCGA tetrad in both sequences. In structures obtained with refined NMR data, CpG adopts, for instance, a greater twist and a higher guanine phase within d(CTTCGAAG)2 compared to d(CATCGATG)2. In the former oligonucleotide, the structure of CpG resembles strikingly that found in the ACGT tetrad of the cAMP responsive element [Mauffret et al. (1992) J. Mol. Biol. 227, 852-875]. Moreover, two conformers with CpG either in the BII state (epsilon, zeta = g-, t) or in the BI state (epsilon, zeta = t, g-) are found equally stable for d(CTTCGAAG)2. The energy barrier from BI to BII comes to only 5.7 kcal/mol, and the path of the transition is very short. When calculations on d(CTTCGAAG)2 are performed taking the BI/BII equilibrium into account, the agreement with both the 1H and 31P data is found better than in the case with a single conformation taken alone. The BI/BII equilibrium may also occur in d(CATCGATG)2, but the amount of BII conformer is now found weaker compared to its analogue. The ability of the CpG phosphate groups to adopt the BII conformation could provide a satisfying explanation for the high mutation rates observed at these sites.
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PMID:Solution structure of the CpG containing d(CTTCGAAG)2 oligonucleotide: NMR data and energy calculations are compatible with a BI/BII equilibrium at CpG. 882 93

The scanning nuclear microprobe (nuclear microscope) is becoming a powerful instrument for the accurate measurement of minor and trace elements in biological tissue. Using the simultaneously applied techniques of Scanning Transmission Ion Microscopy (STIM) to image features in the tissue, Particle induced X-ray emission (PIXE) to measure trace element concentrations, and Rutherford Backscattering Spectrometry (RBS) to characterize the tissue matrix, accurate elemental analysis at the parts per million level can be obtained for most elements. This review describes briefly the results obtained using the nuclear microscope for the elemental analysis of Alzheimer's and Parkinson's tissue. In Alzheimer's disease (AD) the identification and subsequent analysis of neuritic plaque cores in unstained tissue, yielded an absence of aluminium at the limit of 15 parts per million. Previous analyses involving stained sections were prone to misinterpretation due to aluminium contamination from the staining procedures. Elemental iron, calcium, phosphorus and sulphur were elevated both in the plaques and the AD background tissue compared to age matched controls. Preliminary analyses of neurofibrillary tangles stained with toluidine blue showed increased levels of calcium, although the staining procedure may have distorted the results due to element redistribution. In Parkinson's disease (PD) nuclear microscope studies have concentrated on measurements of iron in the substantia nigra (SN) region of the brain; iron was observed to be elevated by a factor 2 in MPTP induced Parkinsonism in African Green monkeys, and by a factor of 1.25 in 6-OHDA induced Parkinsonism in Sprague Dawley rats. These studies are consistent with other studies showing a general increase in the concentrations of iron associated with PD, and support the theory that iron mediated free radical production may enhance or accelerate the degeneration of dopaminergic cells through oxidative stress.
Cell Mol Biol (Noisy-le-grand) 1996 Feb
PMID:Nuclear microscope analysis in Alzheimer's and Parkinson's disease: A review. 883 63


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