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)

Cationic amino acids, arginine and lysine partition differentially from water into aqueous micellar sodium dodecanoate. Conversely, partitioning of serine, glycine, aspartic acid, glutamic acid, threonine, alanine, proline, valine, leucine, phenylalanine and isoleucine do not vary appreciably. Partitioning from neat hexane into dodecylammonium propionate trapped water in hexane is, however, dependent upon both electrostatic and hydrophobic interactions. These results imply that the interior of dedecylammonium propionate aggregates is negatively charged and is capable of hydrogen bonding in addition to providing a hydrophobic enviroment. The solubilities of amino acids in neat hexane substantiate the previously derived amino acid hydrophobicity scale. Relevance of partitioning in these systems to the postulated selective amino acid compartmentalization is discussed.
J Mol Evol 1975 Nov 04
PMID:Compartmentalization of amino acids in surfactant aggregates. Partitioning between water and aqueous micellar sodium deodecanoate and between hexane and dodecylammonium propionate trapped water in hexane. 120 27

1. The pathogenesis of the mental retardation in phenylketonuria remains obscure. Leucocytes have proved of value in the study of other inborn errors of metabolism. The lymphocyte is a suitable model cell for the study of mammalian metabolism, because of its ability to divide in vitro in response to various stimuli. 2. We have examined the effects of phenylalanine, phenylpyruvate, phenyl-lactate and phenylacetate on the human leucocyte and the resting and phytohaemagglutinin-stimulated rabbit lymphocyte. 3. Phenylpyruvate and phenyl-lactate reduced acetate incorporation into leucocyte lipid by 38% and 48% respectively. Only phenyl-lactate reduced acetate incorporation into the resting and stimulated lymphocyte, by 20% and 34% respectively. 4. Glucose incorporation into leucocyte lipid was unaffected by phenylalanine, phenylpyruvate and phenyl-lactate. Only phenyl-lactate inhibited (46%) the production of CO2 from glucose. 5. Phenylalanine and leucine incorporation into trichloroacetic acid-insoluble material of resting and stimulated lymphocytes was inhibited by phenyl-lactate (10-42%), phenylpyruvate (27-57%) and phenylacetate (19-39%). 6. Uridine incorporation into resting and stimulated cells was inhibited by phenyl-lactate (22-26%), phenylpyruvate (42-52%) and phenylacetate (20%). 7. Thymidine incorporation into resting lymphocytes was reduced by phenyl-lactate, phenylpyruvate, phenylacetate and phenylalanine by 12-26%. Incorporation into the stimulated cell was inhibited by phenylpyruvate and phenyl-lactate (90%) and phenylacetate (66%). 8. Phenylalanine inhibited lymphocyte pyruvate kinase and phenylpyruvate inhibited citrate synthetase. 9. These results are compared with published data relating to experimental hyperphenylalaninaemia and the effects of these metabolites on nervous tissue in vitro.
Clin Sci Mol Med 1975 Oct
PMID:Effect of phenylalanine and its metabolites on the metabolism of leucocytes and lymphocytes. 123 28

The effect of secondary stimulation with estrogen on synthesis of nuclear and nucleolar proteins is studied in chick oviduct. Isolated nuclei and nucleoli have a protein/DNA ratio of 5.2 and 5.6, respectively. 35% of nuclear and nucleolar protein is recovered in the histone fraction after hydroxylapatite chromatography. Gel electrophoretic separations of nuclear and nucleolar nonhistones are largely similar as to visible bands and distribution of radioactivity. Nucleoli bind 1.4 times more [3H] estradiol as compared to whole nuclei. Nucleolar histones are labelled slightly more actively with [3H] leucine than nuclear histones; nucleolar nonhistones are labelled about 3 times more actively than nuclear nonhistones. An 18 hour secondary stimulation with estrogen increases the radioactivity of histones by 6-fold and that of nonhistones by 2.5-fold in whole nuclei as well as in nucleoli. Stimulation appears to increase preferentially radioactivity of nonhistones at 50 000 daltons. As this change is observed in whole nuclei and nucleoli and is not reduced with hydroxyurea, it is suggested that this may be related to a gross structural reorganisation of chromatin induced by the hormone.
Mol Cell Biochem 1976 Mar 26
PMID:Labelling of oviduct nuclear and nucleolar proteins during estrogen induced differentiation. 127 54

A model is suggested for the lac repressor binding to the lac operator in which the repressor polypeptide chain sequences from Gly 14 to Ala 32 and from Ala 53 to Leu 71 are involved in specific interaction with operator DNA. A correspondence between the protein and DNA sequences is found which explains specificity of the repressor binding to the lac operator. The model can be extended to describe specific binding of other regulatory proteins to DNA.
Mol Biol Rep 1976 Apr
PMID:A model for the binding of lac repressor to the lac operator. 127 66

1. The combination of a wire-mesh support with the roller-tube technique is described as a procedure for the culture of human jejunal mucosa in vitro. 2. The technique has been applied to fragments (approximately 10 mg) of jejunal biopsies from both normal subjects and patients with coeliac disease. 3. The cultured tissue has been shown by radio-autography to incorporate [3H]leucine into proteins of the villus epithelial cells and [3H]thymidine into nucleic acid, predominantly by the enteroblasts. 4. Although the tissue protein DNA contents fall during culture, it was found that the combined tissue and medium DNA content remained constant during culture and may be used as a reference for enzyme and biochemical studies on cultured intestinal biopsies.
Clin Sci Mol Med 1976 May
PMID:Biochemical and morphological studies on human jejunal mucosa maintained in culture. 127 50

Various polyoxometalates proved inhibitory to the replication of a number of enveloped DNA and RNA viruses, i.e., herpesviruses (herpes simplex and cytomegalo), togaviruses (Sindbis), paramyxoviruses (respiratory syncytial), rhabdoviruses (vesicular stomatitis), arenaviruses (Junin and Tacaribe), and retroviruses [human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2), simian immunodeficiency virus, and murine sarcoma virus]. The most potent compounds, i.e., JM1590 [K13[Ce(SiW11O39)2]. 26H2O] and JM2766 [K6[BGa(H2O)W11O39]. 15H2O], inhibited HIV-1 and simian immunodeficiency virus at concentrations as low as 0.008-0.8 microM. The polyoxometalates also inhibited giant cell formation in co-cultures of HIV-infected HUT-78 cells and uninfected MOLT-4 cells. Studies designed to unravel the mechanism of action of these compounds revealed that they inhibit the reverse transcriptase activity associated with HIV. The polyoxometalates also proved inhibitory to the binding of HIV-1 virions to the cells. From "time of addition" experiments, whereby the polyoxometalates were added at different times after virus infection, their mechanism of anti-HIV action could be attributed to inhibition of virus-cell binding. There was a good correlation (r = 0.84) between the inhibitory effects of the compounds on HIV-1-induced cytopathicity and their inhibitory effects on syncytium formation and a close correlation (r = 0.902) between their inhibitory effects on syncytium formation and their interaction with gp120, whereas there was no correlation between their anti-HIV-1 activity and their inhibitory effects on HIV-1 reverse transcriptase. In flow cytometric studies, the compounds did not interfere with the binding of OKT4A/Leu-3a monoclonal antibody to the CD4 receptor of uninfected cells, but they inhibited binding of anti-gp120 monoclonal antibody to HIV-1-infected cells. Thus, the binding of the polyoxometalates to the viral envelope glycoprotein gp120 is responsible for their anti-HIV activity.
Mol Pharmacol 1992 Dec
PMID:Mechanism of anti-human immunodeficiency virus action of polyoxometalates, a class of broad-spectrum antiviral agents. 128 64

The present study examines the basal and gonadotrophin-releasing hormone (GnRH)-stimulated biosynthesis and release of luteinizing hormone (LH) by pituitary cells in primary culture, and the effect of extracellular calcium deprivation on these events. Pituitaries from ovariectomized adult rats were enzymatically dispersed and cultured for 96 h. The cells were then incubated for 5 h (Expts. 1 and 3) or for different time intervals between 0 and 5 h (Expt. 2), in medium containing [14C]leucine ([14C]leu) and [3H]glucosamine ([3H]gln), with or without GnRH. Total immunoreactive LH (iLH) was measured in the medium and the cell extract by radioimmunoassay. LH translation (as estimated by [14C]leu incorporation into LH; [14C]LH) and LH glycosylation (as estimated by [3H]gln incorporation into LH; [3H]LH) were measured by immunoprecipitation with specific LH beta antiserum in both medium and cell extract. Treating the cells with GnRH caused both time- and dose-dependent increases of iLH in the medium as well as in total (cells plus medium) content, with an approximate ED50 of 0.7 nM. GnRH also stimulated LH biosynthesis by increasing both LH polypeptide chain synthesis and LH glycosylation. The effect of GnRH on LH glycosylation was detected earlier than that on translation, the [3H]LH rates of production and release being higher than those of [14C]LH. These findings suggest that GnRH-induced translation and glycosylation of LH are independently regulated. Removal of extracellular calcium resulted in the loss of cellular responsiveness to GnRH, preventing not only the stimulatory effects of GnRH on total and released iLH but also the GnRH-induced incorporation of both [14C]leu and [3H]gln into newly synthesized LH. These observations suggest that GnRH-stimulated LH glycosylation and LH translation involve calcium-dependent mechanisms. Neither the uptake of radiolabeled precursors nor their incorporation into total protein were affected by GnRH or Ca(2+)-deficient (no added calcium) medium. The results also suggest that the release of newly synthesized LH is regulated differently from previously synthesized stored hormone.
Mol Cell Endocrinol 1992 Nov
PMID:Basal and gonadotrophin-releasing hormone-induced biosynthesis and release of luteinizing hormone: effect of calcium deprivation. 130 81

The crystal structure of RNase H from Escherichia coli has been determined by the multiple isomorphous replacement method, and refined by the stereochemically restrained least-squares procedure to a crystallographic R-factor of 0.196 at 1.48 A resolution. In the final structure, the root-mean-square (r.m.s.) deviation for bond lengths is 0.017 A, and for angle distances 0.036 A. The structure is composed of a five-stranded beta-sheet and five alpha-helices, and reveals the details of hydrogen bonding, electrostatic and hydrophobic interactions between intra- and intermolecular residues. The refined structure allows an explanation of the particular interactions between the basic protrusion, consisting of helix alpha III and the following loop, and the remaining major domain. The beta-sheet, alpha II, alpha III and alpha IV form a central hydrophobic cleft that contains all six tryptophan residues, and presumably serves to fix the orientation of the basic protrusion. Two parallel adjacent helices, alpha I and alpha IV, are associated with a few triads of hydrophobic interactions, including many leucine residues, that are similar to the repeated leucine motif. The well-defined electron density map allows detailed discussion of amino acid residues likely to be involved in binding a DNA/RNA hybrid, and construction of a putative model of the enzyme complexed with a DNA/RNA hybrid oligomer. In this model, a protein region, from the Mg(2+)-binding site to the basic protrusion, covers roughly two turns of a DNA/RNA hybrid double helix. A segment (11-23) containing six glycine residues forms a long loop between the beta A and beta B strands. This loop, which protrudes into the solvent region, lies on the interface between the enzyme and a DNA/RNA hybrid in the model of the complex. The mean temperature factors of main-chain atoms show remarkably high values in helix alpha III that constitutes the basic protrusion, suggesting some correlation between its flexibility and the nucleic acid binding function. The Mg(2+)-binding site, surrounded by four invariant acidic residues, can now be described more precisely in conjunction with the catalytic activity. The arrangement of molecules within the crystal appears to be dominated by the cancelling out of a remarkably biased charge distribution on the molecular surface, which is derived in particular from the separation between the acidic Mg(2+)-binding site and the basic protrusion.
J Mol Biol 1992 Feb 20
PMID:Structural details of ribonuclease H from Escherichia coli as refined to an atomic resolution. 131 86

Many natural DNA sequences are restricted in Escherichia coli K-12, not only by the classic Type I restriction system EcoK, but also by one of three modification-specific restriction systems found in K-12. The McrBC system is the best studied of these. We infer from the base composition of the mcrBC genes that they were imported from an evolutionarily distant source. The genes are located in a hypervariable cluster of restriction genes that may play a significant role in generation of species identity in enteric bacteria. Restriction activity requires the products of two genes for activity both in vivo and in vitro. The mcrB gene elaborates two protein products, only one of which is required for activity in vitro, but both of which contain a conserved amino acid sequence motif identified as a possible GTP-binding site. The mcrC gene product contains a leucine heptad repeat that could play a role in protein-protein interactions. McrBC activity in vivo and in vitro depends on the presence of modified cytosine in a specific sequence context; three different modifications are recognized. The in vitro activity of this novel multi-subunit restriction enzyme displays an absolute requirement for GTP as a cofactor.
Mol Microbiol 1992 May
PMID:Organization and function of the mcrBC genes of Escherichia coli K-12. 131 84

A non-sporulating mutant (whiB218) of Streptomyces coelicolor A3(2), which proved to contain a deletion of more than 5 kb of DNA including whiB, was complemented by a small cloned DNA fragment, deduced from DNA sequencing to encode a protein of only 87 amino acids. This protein would bear some similarities to transcription factors, including an acidic, somewhat amphipathic alpha-helical region predicted near its N-terminus, and a basic alpha-helical region predicted at its C-terminus. A point mutation (whiB70) giving a phenotype indistinguishable from that of the whiB218 deletion mutant would cause a leucine to proline change at the start of the latter region. The whiB homologue from the closely related species S. lividans differed at only one base from its S. coelicolor counterpart, and would specify an identical polypeptide.
Mol Gen Genet 1992 Apr
PMID:The Streptomyces coelicolor whiB gene encodes a small transcription factor-like protein dispensable for growth but essential for sporulation. 131 97


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