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)

A broad-spectrum mercury resistance locus (mer) from a spontaneous chloramphenicol-sensitive (Cms), arginine auxotrophic (Arg-) mutant of Streptomyces lividans 1326 was isolated on a 6 kb DNA fragment by shotgun cloning into the mercury-sensitive derivative S. lividans TK64 using the vector pIJ702. The mer genes form part of a very large amplifiable DNA sequence present in S. lividans 1326. This element was amplified to about 20 copies per chromosome in the Cms Arg- mutant and was missing from strains like S. lividans TK64, cured for the plasmid SLP3. DNA sequence analysis of a 5 kb region encompassing the whole region required for broad-spectrum mercury resistance revealed six open reading frames (ORFs) transcribed in opposite directions from a common intercistronic region. The protein sequences predicted from the two ORFs transcribed in one direction showed a high degree of similarity to mercuric reductase and organomercurial lyase from other gram-negative and gram-positive sources. Few, if any, similarities were found between the predicted polypeptide sequences of the other four ORFs and other known proteins.
Mol Gen Genet 1992 Dec
PMID:Cloning and DNA sequence analysis of the mercury resistance genes of Streptomyces lividans. 149 53

Our knowledge concerning the pathology of fetal cases of human Minamata disease (methylmercury poisoning) is relatively limited. We report here a case with description of the distribution of mercury in the systemic organs, and the ultrastructural changes of the nervous system after a survival of 29 yr. The patient was a female born in 1957, with a body wt of 3000 g, who died in 1987. She carried a diagnosis of cerebral palsy, and had a convulsion at age 3 yr. Mercury levels in her mother's hair were 101 micrograms/g at the time of examination in 1959. At autopsy, the body measured 43 cm and weighed 23 kg. The brain weighed 920 g and showed marked cerebral atrophy, mild neuronal loss in the calcarine, postcentral and precentral cortices, cerebellar atrophy, and segmental demyelination of peripheral nerves. Mercury granules were present in the brain, kidney, and liver. Ultrastructural examination of the calcarine, post- and precentral cortices, and cerebellar cortices, showed severe atrophy of nerve cells, with a decrease in rough ER and an increase in nuclear chromatin and preservation of mitochondria. Autophagosomes were increased in number. In addition, high electron density, globular and dense bodies, measuring 0.3-1.8 microns in diameter, were found, surrounded by limited membrane, within both cerebral and cerebellar neurons. In the cellebellum, synapses were well-preserved.
Mol Chem Neuropathol
PMID:A fetal type of Minamata disease. An autopsy case report with special reference to the nervous system. 152 Apr 2

We have employed the rapid-freeze technique to prepare specimens for electron microscopy of a coat protein solution of tobacco mosaic virus at equilibrium at pH 7.0 and 6.8, ionic strength 0.1 M and 20 degrees C. The former are the conditions for the most rapid assembly of the virus from its isolated protein and RNA. At both pH values, the equilibrium mixture contains approximately 80% of a "20 S" aggregate and 20% of a "4 S" aggregate (the so-called A-protein). The specimens were prepared either totally unstained or positively stained with methyl mercury nitrate, which binds to an amino acid residue (Cys27) internally located within the subunit, which we show not to affect the virus assembly. The images in the electron microscope are compatible only with the major structure for the "20 S" aggregate at pH 7.0 containing two rings of subunits and these aggregates display the same binding contacts as those seen between the aggregate that forms the asymmetric unit in the crystal, which has been shown by X-ray crystallography to be a disk containing two rings, each of 17 subunits, oriented in the same direction. In contrast, the images from specimens prepared at pH 6.8 show the major structure to be a proto-helix at this slightly lower pH, demonstrating that the technique of cryo-electron microscopy is capable of distinguishing between these aggregates of tobacco mosaic virus coat protein. The main structure in solution at pH 7.0 must therefore be very similar to that in the crystal, although slight differences could occur and there are probably other, minor, components in a mixture of species sedimenting around 20 S under these conditions. The equilibrium between aggregates is extremely sensitive to conditions, with a drop of 0.2 pH unit tipping the disk to proto-helix ratio from approximately 10:1 at pH 7.0 to 1:10 at pH 6.8. This direct determination of the structure of the "20 S" aggregate in solution, under conditions for virus assembly, contradicts some recent speculation that it must be helical, and establishes that, at pH 7.0, it is in fact predominantly a two-layer disk as it had been modelled before.
J Mol Biol 1992 Mar 20
PMID:Direct visualization of the structure of the "20 S" aggregate of coat protein of tobacco mosaic virus. The "disk" is the major structure at pH 7.0 and the Proto-helix at lower pH. 156 Apr 58

Filamentous bacteriophage M13 is a single-stranded DNA phage about 65 A in diameter and 9300 A long. X-ray diffraction studies of magnetically oriented fibers of native, mercury and iodine-labeled phage particles have been used to determine the arrangement of the major coat protein, the gene 8 product, in the virion. The coat protein is made up of a single gently curving alpha-helix extending from approximately Pro6 to near the carboxyl terminus. The axis of the alpha-helix is tilted about 20 degrees from the viral axis and wraps around the axis in a right-handed helical sense. The surface of the virus is made up largely of polar residues in the amino-terminal half of the protein including the segment of alpha-helix extending from Pro6 to Tyr24. The interior surface of the protein coat faces the DNA and consists of an amphipathic helical segment extending from Thr36 to Ser50. The alpha-helices form a tightly packed 15 to 20 A thick cylindrical coat around the DNA. This structural model provides insight into the potential sites for incorporating foreign protein domains that may act as functional binding sites on the surface of M13.
J Mol Biol 1992 Jul 20
PMID:Three-dimensional structure of a cloning vector. X-ray diffraction studies of filamentous bacteriophage M13 at 7 A resolution. 164 Apr 60

In an accompanying paper a computational procedure is described, which introduces new ligand-binding sites into proteins of known structure. Here we describe the experimental implementation of one of the designs, which is intended to introduce a copper-binding site into Escherichia coli thioredoxin. The new binding site can be introduced with a minimum of four amino acid changes. The binding site is buried so that structural rules for making mutations in the hydrophobic core of a protein, as well as for the introduction of new functions, are being tested in this experiment. The mutant protein is folded even in the absence of metals, and variants that retain the original activity of thioredoxin can be isolated. The protein has gained a metal-binding site specific for transition metals. The metal co-ordination chemistry at the binding site varies depending on the metal that is introduced into it. Mercury(II) is co-ordinated in the expected manner. Copper(II) binds in a way that was not anticipated in the original design. It appears to use two of the four residues intended to form the co-ordination sphere, and two other residues that were not part of the original set of mutations. It is therefore necessary not only to introduce new functional groups to form a new site, but also to consider and remove alternative modes of binding.
J Mol Biol 1991 Dec 05
PMID:Construction of new ligand binding sites in proteins of known structure. II. Grafting of a buried transition metal binding site into Escherichia coli thioredoxin. 166 Sep 33

In order to study the effects of trans-acting factors on cis-acting elements in plant genes an in vitro reinitiating nuclear transcription system is needed. Here we report that run-on experiments with nuclei isolated from 2,4-D-treated auxin-starved early-stationary-phase cells of tobacco clearly show reitintiation of transcription of specific 2,4-D-induced genes. Using gamma-thio nucleotides and [alpha-32P]-UTP we were able to demonstrate the presence of reinitiated labelled specific RNAs after isolation on a mercury-agarose affinity column. Addition of heparin as an inhibitor blocked this reinitiation. In a primer extension assay we found that the new transcripts initiate at approximately the same site as used in vivo.
Plant Mol Biol 1992 Jan
PMID:Specific transcription and reinitiation of 2,4-D-induced genes in tobacco nuclei. 173 62

An X-ray crystallographic structure determination has been carried out on bovine lens leucine aminopeptidase at 4.0 A resolution by using a combination of isomorphous replacement and solvent flattening. The two heavy atom derivatives used were obtained by soaking crystals in ethyl mercury chloride, which bound at four sites, and phenyl mercury acetate, which bound at one site in the monomer. The electron density map reveals that the enzyme hexameric oligomer, arranged in 32 symmetry, has a triangular barrel appearance and dimensions, of height 88 A and maximal width 118 A in barrel equatorial plane. Each subunit in an elongated ellipsoid of approximate length 92 A. Subunits contacts have been described. From an analysis of the map each subunit appears to contain some 36% alpha-helix and is organized into two distinct globular domains. Direct location of zinc cluster and competitive inhibitor binding site are presented.
Mol Biol (Mosk)
PMID:[X-ray structural study of leucine aminopeptidase with a resolution of 4 Angstroms]. 179 3

HgCl2 resistance (Hgr) in a strain of Pseudomonas putrefaciens isolated from the River Mersey was identified as plasmid-borne by its transfer to Escherichia coli in conjugative matings. This plasmid, pMERPH, could not be isolated and was incompatible with the chromosomally integrated IncJ Hgr plasmid R391. pMERPH and R391 both express inducible, narrow-spectrum mercury resistance and detoxify HgCl2 by volatilization. The cloned mer determinants from pMERPH (pSP100) and R391 (pSP200) have very similar restriction maps and express identical polypeptide products. However, these features show distinct differences from those of the Tn501 family of mer determinants. pSP100 and pSP200 failed to hybridize at moderate stringency to merRTPA and merC probes from Tn501 and Tn21, respectively. We conclude that the IncJ mer determinants are only distantly related to that from Tn501 and its closely homologous relatives and that it identifies a novel sequence which is relatively rare in bacteria isolated from natural environments.
Mol Gen Genet 1991 Aug
PMID:Novel mercury resistance determinants carried by IncJ plasmids pMERPH and R391. 188 14

The histochemical technique of autometallography was used in the present study to demonstrate the zonal and tubular localization of inorganic mercury in the kidneys of unilaterally nephrectomized (NPX) and sham-operated (SO) rats given either a nontoxic 0.5 mumol/kg or a toxic 2.5 mumol/kg dose of mercuric chloride 10 days after surgery. Deposits were found in the cortex and outer stripe of the outer medulla in both groups of rats given either dose of mercuric chloride. The deposits were localized exclusively in the convoluted and straight portion of the proximal tubule. Forty eight hours after the administration of the 0.5 mumol/kg dose of mercuric chloride, there were significantly more deposits in the renal outer stripe of the NPX rats than in the renal outer stripe of the SO rats. The number of deposits in the renal outer stripe of the NPX and SO rats given the 2.5 mumol/kg dose of mercuric chloride was similar after 24 hr, but was greater than the corresponding rats given the nontoxic dose. These findings suggest that the proximal tubule (particularly the pars recta) is the primary site for the accumulation of inorganic mercury in the kidney. They also suggest that, in the rat, there is enhanced accumulation of inorganic mercury in the pars recta of proximal tubules in the outer stripe of the renal outer medulla when a nontoxic dose of inorganic mercury is given after unilateral nephrectomy or when a toxic dose of mercuric chloride is administered.
Exp Mol Pathol 1991 Feb
PMID:Autometallographic localization of inorganic mercury in the kidneys of rats: effect of unilateral nephrectomy and compensatory renal growth. 199 16

Methylmercury accumulation in different parts of the CNS (olfactory bulbs, cerebral hemispheres, cerebellum, medulla oblongata and spinal cord) in relation to the cytoarchitectural changes in myelin sheath as well as in glycosidases levels have been reported. Male albino rats were treated with low and high doses of methylmercury chloride (1 mg/kg and 10 mg/kg) N-acetyl-DL-homocysteine thiolactone (40 mg/kg and 80 mg/kg) and glutathione (100 mg/kg and 150 mg/kg) for varied time periods. The study shows a dose and duration dependent accumulation of mercury in all the CNS areas coinciding with a progressive myelin degeneration and inhibition of the glycosidases. A casual relationship between the amount of mercury accumulation and the extent of enzymes inhibition, in any particular area of CNS, could not be established. Similarly none of the antagonists is (though has been successful in recovering the enzymes and lessening the mercury burden in a few isolated cases) able to bring an absolute control value in any group.
Cell Mol Biol 1990
PMID:Dose and duration related methylmercury deposition, glycosidases inhibition, myelin degeneration and chelation therapy. 207 85


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