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)

Rhizobium bacteria form nitrogen-fixing nodules on legume roots. As part of the nodulation process, they secrete Nod factors that are beta-1,4-linked oligomers of N-acetylglucosamine. These factors depend on nodulation (nod) genes, but most aspects of factor synthesis are not yet known. We show here that one gene, nodC, shows striking similarity to genes encoding proteins known to be involved in polysaccharide synthesis in yeast and bacteria, specifically chitin and cellulose synthases, as well as a protein with unknown function in Xenopus embryos, DG42. This similarity is consistent with a role for the NodC protein in the formation of the beta-1,4-linkage in Nod factors.
Mol Plant Microbe Interact
PMID:Homology of Rhizobium meliloti NodC to polysaccharide polymerizing enzymes. 147 20

The antineoplastic drug estramustine is an adduct of estradiol and nor-nitrogen mustard. It has been shown that this drug interferes with microtubule assembly, an effect mediated by estramustine interaction with microtubule-associated proteins (MAPs). In the present report we demonstrate that estramustine and the phosphorylated derivative of the drug, estramustine-phosphate, inhibit the secretion of interleukin-3 by WEHI-3B cells. These studies also show that the estramustine derivative specifically interacts with a MAPs component found in these cells, which exhibited characteristics ressembling those of tau protein isoforms. Western blots using a unique monoclonal antibody MTB6.22 that recognizes microtubule-binding domains on MAPs, indicated that this WEHI protein factor contained the antigenic determinant that are functionally significant for microtubule assembly. ELISA assays using this antibody, also showed a decrease in the levels of the immunoreactive protein in WEHI cells after treatment with EMP. Interestingly, it has been recently described that the action of estramustine-phosphate is mediated by a direct interaction with MAP-binding sites on the microtubule surface, which are recognized by the site-specific monoclonal antibody. These findings together with immuno-precipitation experiments using anti-interleukin-3 antibodies and the inhibitory effect of the estramustine derivative on WEHI secretion process suggest that this anti-mitotic agent may block IL-3 secretion by a mechanism involving its interaction with a 'tau-like' MAPs component present in these cells.
Mol Cell Biochem 1992 Nov 18
PMID:The antineoplastic agent estramustine and the derivative estramustine-phosphate inhibit secretion of interleukin-3 in leukemic cells. Possible roles of MAPs. 148 50

The effect of hypoxia on the incorporation of [14C]serine into serine glycerophospholipids was investigated in rat brain cortex. Brain slices were incubated, in the presence of the labeled precursor, in Krebs-Henseleit Ringer bicarbonate or Krebs Ringer phosphate, and hypoxia was induced by bubbling nitrogen in the medium. The lowering of oxygen caused an increase of the incorporation of the base into phosphatidylserine in slices incubated in both media, although the effect was greater in Krebs Ringer phosphate. Such an effect was also observed in the homogenate subjected to N2-treatment, with an increase in the incorporation similar to that obtained in slices incubated in Krebs-Henseleit Ringer bicarbonate. Phosphatidylserine is synthesized in mammalian tissues by a "base-exchange" enzyme, strictly Ca2+ dependent, and, moreover, is necessary for protein kinase C activity. We postulate that the increased synthesis of phosphatidylserine might affect signal transduction mechanisms and participate in the modification of lipid metabolism observed in hypoxia and/or ischemia.
Mol Chem Neuropathol 1992 Dec
PMID:Serine incorporation into phosphatidylserine in hypoxic rat brain cortex. 149 81

When Neurospora crassa is transformed using a Neurospora gene as the selectable marker, the vegetatively stable transformants obtained cannot be used successfully in a cross because the selectable marker will be inactivated by the process of RIP (repeat-induced point mutation). Introduction of the acetamidase-encoding gene amdS of Aspergillus nidulans into N. crassa by transformation yielded transformants that would grow in minimal medium containing acetamide as a sole nitrogen source. In mitotically stable transformants containing a single copy of the amdS gene, the capacity to utilize acetamide as a sole nitrogen source was maintained in the progeny of a sexual cross. Therefore, the A. nidulans amdS gene is an appropriate dominant selectable marker for use in transformation analyses with N. crassa in which sexual crosses will be subsequently performed.
Mol Gen Genet 1992 Dec
PMID:A dominant selectable marker that is meiotically stable in Neurospora crassa: the amdS gene of Aspergillus nidulans. 149 42

The alternative sigma factor sigma 54 is required for transcription of nitrogen fixation genes in Klebsiella pneumoniae and other diazotrophs. The nif genes, and other E sigma 54-dependent genes whose products are necessary for a wide range of processes, are postively regulated. A unifying model that is well supported by studies on nif and other nitrogen-regulated (ntr) genes includes the central tenet that sigma 54 confers upon core RNA polymerase the ability to recognize and bind specific promoter sequences, but not the ability to isomerize to the open complex without assistance from the appropriate activator protein. Direct physical evidence for formation of an activator-independent complex between E sigma 54 and the NifA-dependent K. pneumoniae nifH and nifU promoters has, to date, been lacking. Using purified components we have now demonstrated formation of the closed complex at these promoters, indicating that it is an intermediate along the pathway to open complex formation. The closed complex was not detected when conserved features of the promoter were altered by mutation, nor was its stability increased when integration host factor protein was bound adjacent to the E sigma 54 recognition sequence.
Mol Microbiol 1992 Jun
PMID:Activator-independent formation of a closed complex between sigma 54-holoenzyme and nifH and nifU promoters of Klebsiella pneumoniae. 149 90

Five regions of the Bradyrhizobium japonicum genome, which are transcribed at high levels in nitrogen-fixing soybean (Glycine max) nodules, were identified. None of these regions contained previously identified genes (e.g., nif, nod, and fix genes) that are known to be essential for development of functional nitrogen-fixing nodules. To assess the role of these regions in the development of the B. japonicum-soybean symbiosis, we cloned and used them to construct B. japonicum strains, in which large DNA segments (2.0-6.8 kilobases) containing the highly transcribed regions were deleted. The deletion strains were examined for symbiotic effectiveness and were found to be indistinguishable from the wild-type strain. Transcription of the cloned regions under a variety of physiological conditions and in several defined mutant B. japonicum strains was also examined. The transcriptional start sites for one pair of divergent transcripts were determined; the promoters do not contain any of the conserved sequences found in B. japonicum genes involved in symbiosis or nitrogen metabolism.
Mol Plant Microbe Interact
PMID:Analysis of DNA sequences transcribed at high levels in Bradyrhizobium japonicum bacteroids but not necessary for symbiotic effectiveness. 151 66

The CHARGE2 program for the calculation of partial atomic charges has been amended to include bond parameters for a number of organic functional groups, including halogens, nitrogen and oxygen. These minor amendments to the original scheme produce dipole moments for the fluoro and chloro compounds which are in complete agreement with the observed values. The less complete data sets for the bromo and iodo compounds are also well reproduced, and the dipole moments of a variety of mixed halo compounds are now in better agreement with experiment than previously. The calculated dipole moments of the saturated nitrogen and oxygen compounds are now in much better agreement than in the original scheme, thus the revised parameterisation may be employed with confidence to predict the electrostatic energies of these compounds. Furthermore, the revised scheme now gives a precise proportionality between the charge on the proton in a CH group and the 1H chemical shift of the corresponding proton, allowing the general prediction, in principle, of 1H chemical shifts. In addition, attempts to include variable electronegativity in the alpha effect are described for fluoro compounds.
J Comput Aided Mol Des 1992 Jun
PMID:Charge calculations in molecular mechanics. IX. A general parameterisation of the scheme for saturated halogen, oxygen and nitrogen compounds. 151 78

Systematic series of monoamines, diamines, and triamines were used to define the structural requirements for interaction at the polyamine recognition site of the N-methyl-D-aspartate receptor complex. Effects of amines on binding of [3H]MK-801 to washed synaptic plasma membranes were measured in the presence of L-glutamate and glycine (100 microM each), in the absence or presence of spermine (10 microM). Linear aliphatic monoamines of methylene chain length up to 12 (dodecylamine) did not interact with the polyamine recognition site. Nonspecific inhibition of binding was observed at high concentrations of the longer monoamines. alpha,omega-Diamines of methylene chain length 2 (1,2-diaminoethane, DA2) through 12 (1,12-diaminododecane, DA12) had varying actions, depending on chain length. The shortest diamines (DA2 and DA3) acted as weak partial agonists, enhancing the binding of [3H[MK-801. Intermediate-length diamines (DA4-DA7) were selective polyamine antagonists, having little or no effect on binding of [3H]MK-801 measured in the absence of spermine but inhibiting binding measured in the presence of spermine. The longest diamines tested (DA8-DA12) acted as inverse agonists; they inhibited binding in the absence or presence of spermine, and this inhibition was blocked by the selective polyamine antagonist diethylenetriamine. Computer modeling of conformations of the diamines quantitatively documented that 1) these molecules are flexible and 2) long diamines may easily adopt conformations with inter-nitrogen distances mimicking those of short diamines. The cis and trans isomers of 1,4-diaminocyclohexane are inflexible, conformationally restricted diamines with markedly different actions. The cis isomer was a partial agonist and the trans isomer was an antagonist at the polyamine recognition site. Triamines of general structure NH2(CH2)3NH(CH2)xNH2 (TRI[3,x]), in which x = 3-12, were synthesized and tested for activity at the polyamine recognition site. Despite the large range of size, TRI[3,3] through TRI[3,9] were all fully polyamine agonists of similar potency. TRI[3,10] was a partial agonist, whereas TRI[3,12] inhibited binding of [3H]MK-801. Diethylenetriamine did not attenuate the effect of TRI[3,12]. Based on the results of the radioligand binding studies and the computer analysis, a model of the polyamine recognition site is proposed.
Mol Pharmacol 1992 Apr
PMID:Effects of mono-, di-, and triamines on the N-methyl-D-aspartate receptor complex: a model of the polyamine recognition site. 153 70

A 4 kb SalI fragment from Azospirillum brasilense Sp7 that shares homology with a 6.8 kb EcoRI fragment carrying nodGEFH and part of nodP of Rhizobium meliloti 41 was cloned in pUC18 to yield pAB503. The nucleotide sequence of a 2 kb SalI-SmaI fragment of the pAB503 insert revealed an open reading frame, named ORF3, encoding a polypeptide sharing 40% identity with R. meliloti NodG. The deduced polypeptide also shared 60% identity with the Alcaligenes eutrophus NADPH-dependent acetoacetyl-CoA (AA-CoA) reductase, encoded by the phbB gene and involved in poly-beta-hydroxybutyrate (PHB) synthesis. Northern blot analysis and promoter extension mapping indicated that ORF3 is expressed as a monocistronic operon from a promoter that resembles the Escherichia coli sigma 70 consensus promoter. An ORF3-lacZ translational fusion was constructed and was very poorly expressed in E. coli, but was functional and constitutively expressed in Azospirillum. Tn5-Mob insertions in ORF3 did not affect growth, nitrogen fixation, PHB synthesis or NAD(P)H-linked AA-CoA reductase activity. An ORF3 DNA sequence was used to probe total DNA of several Azospirillum strains. No ORF3 homologues were found in A. irakense, A. amazonense, A. halopraeferens or in several A. lipoferum strains.
Mol Gen Genet 1992 Feb
PMID:Characterization of an Azospirillum brasilense Sp7 gene homologous to Alcaligenes eutrophus phbB and to Rhizobium meliloti nodG. 153 94

The nucleotide sequence required for a fully functional promoter and operator of the Pseudomonas aeruginosa argF gene (argFpo), the arginine-repressible gene for anabolic ornithine carbamoyltransferase, was defined within a 160 bp region. The streptomycin (Sm) resistance genes strAB of plasmid RSF1010 were fused to argFpo. This construct in P. aeruginosa strain PAO conferred resistance to Sm. Mutants of strain PAO were selected which were resistant to Sm in the presence of arginine due to constitutive expression of argFpo-strAB. These mutants were designated argR. They were unable to grow or grew poorly on arginine or ornithine as the sole carbon and nitrogen source. This growth defect (Aru-/Oru- phenotype) was correlated with a reduced level of N-succinylornithine aminotransferase, an enzyme participating in the major aerobic pathway for arginine and ornithine catabolism in this organism. The argR mutants were classified into four groups by transduction analysis and three argR mutations were mapped on the PAO chromosome. argR9901 and argR9902 were co-transducible with car-9 (at 1 min) and thus close to the oru-310 locus; argR9906 was localized in the oruI (= aru) gene cluster (67 min). Some aru mutants, which have been isolated previously and which produce very low amounts of all enzymes in the arginine succinyltransferase pathway, were unable to repress the argF gene in an arginine medium. Thus, P. aeruginosa PAO appears to have multiple genes that are involved in the regulation of both the anabolic argF and the catabolic aru genes.
Mol Gen Genet 1992 Feb
PMID:Mutations affecting regulation of the anabolic argF and the catabolic aru genes in Pseudomonas aeruginosa PAO. 153 97


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