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Query: UNIPROT:P06889 (
Mol
)
630,302
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The symmetric (v1) and antisymmetric (v3) stretching bands of water monomers in
toluene
are revisited using two approaches: (i) calculation of dipole autocorrelation functions (ii) the solvatochromic behaviour of both vibration frequency shifts. The time constants extracted from the autocorrelations account for meaningful differences between the couplings established by the antisymmetric and symmetric vibrations with the solvent. The dipole autocorrelation function for the symmetric stretching band fits well a Lorentzian spectral density and shows a higher contribution to hindered rotation relatively to the one obtained from the antisymmetric stretching. The spectral shifts of stretching frequencies in
toluene
and in other relevant solvents were interpreted as arising from the electronic and orientational polarisations. Characteristic donor/acceptor interactions also contribute to the red shift and were tested by using empirical solvent basicity scales such as Kamlet-Taft beta and the recently proposed SB. The deviations detected in
toluene
as regards the continuum dielectric predictions are quantitatively treated and account for the specific interaction between the water and the molecular pi electron system referred to in the literature.
Spectrochim Acta A
Mol
Biomol Spectrosc 2001 Jan
PMID:Water in toluene revisited: vibrational patterns in the stretching region. 1120 55
Pseudomonas putida DOT-T1E grows on a water-
toluene
double liquid phase.
Toluene
tolerance in this microorganism is mainly achieved by at least two efflux pumps that belong to the RND family. The TtgDEF efflux pump is induced by
toluene
, whereas the other efflux pump, called TtgABC, is expressed at a high level in cells not exposed to
toluene
and at a lower level in cells grown with
toluene
. The ttgR gene is adjacent to the ttgABC operon and is transcribed divergently from ttgA. The expression level of ttgR was fourfold higher in cells growing in the presence of
toluene
than in its absence. In a TtgR-deficient background, expression from the ttgA promoter increased about 20-fold, suggesting that TtgR represses expression from the ttgA promoter. In this mutant, background expression of the ttgR gene was also much higher than in the wild-type background; however, its level of expression increased in the presence of
toluene
. In a ttgR mutant background, expression from the ttgD promoter followed the same pattern of expression as in the wild type. Analysis of a P. putida pTn5cat mutant that exhibited increased sensitivity to a sudden
toluene
shock, regardless of whether or not it was previously exposed to low
toluene
concentrations, revealed that pTn5cat had interrupted an lrp-like gene. The ttgR gene was expressed at very high levels in this mutant, with concomitant repression of expression of the ttgABC operon. The second ttgDEF efflux pump was expressed at low levels in this mutant strain, suggesting that the Lrp-like protein is a global regulatory protein involved in the solvent-tolerant response of this strain.
Mol
Microbiol 2001 Feb
PMID:Global and cognate regulators control the expression of the organic solvent efflux pumps TtgABC and TtgDEF of Pseudomonas putida. 1125 28
In the presence of benzene,
toluene
, m-xylene, mesitylene and durene, the pyrrolic NH stretching band of betacarboline, 9H-pyrido[3,4-b]indole, and its 1-methyl derivative, harmane, in tetrachloroethane diminishes in intensity while a new red-shifted band grows up. The shifts of the associated bands increase linearly with the pi-electron density of the substrates. These spectral changes are attributed to the formation of 1:1 molecular association complexes between the betacarbolines and the benzenoid substrates. The complexes are stabilized by the hydrogen-bonding interaction between the pyrrolic NH group of betacarboline and the pi-delocalized electrons of the benzene derivatives. The influence of these NH/pi hydrogen-bonding interactions in the fluorescence spectra of betacarboline is discussed.
Spectrochim Acta A
Mol
Biomol Spectrosc 2001 Apr
PMID:Hydrogen bonding NH/pi interactions between betacarboline and methyl benzene derivatives. 1137 64
High-field and -frequency electron paramagnetic resonance (HFEPR) spectroscopy has been used to study three complexes of high spin Manganese(III), 3d4, S = 2. The complexes studied were tetraphenylporphyrinatomanganese(III) chloride (MnTPPCI), phthalocyanatomanganese(III) chloride (MnPcCl), and (8,12-diethyl-2,3,7,13,17,18-hexamethylcorrolato)manganese(III) (MnCor). We demonstrate the ability to obtain both field-oriented (single-crystal like) spectra and true powder pattern HFEPR spectra of solid samples. The latter are obtained by immobilizing the powder, either in an n-eicosane mull or KBr pellet. We can also obtain frozen solution HFEPR spectra with good signal-to-noise, and yielding the expected true powder pattern. Frozen solution spectra are described for MnTPPCl in 2:3 (v/v)
toluene
/CH2Cl2 solution and for MnCor in neat pyridine (py) solution. All of the HFEPR spectra have been fully analyzed using spectral simulation software and a complete set of spin Hamiltonian parameters has been determined for each complex in each medium. Both porphyrinic complexes (MnTPPCl and MnPcCl) are rigorously axial systems, with similar axial zero-field splitting (zfs): D approximately -2.3 cm(-1), and g values quite close to 2.00. In contrast, the corrole complex, MnCor, exhibits slightly larger magnitude, rhombic zfs: D approximtely -2.6 cm(-1), absolute value(E) approximately 0.015 cm(-1), also with g values quite close to 2.00. These results are discussed in terms of the molecular structures of these complexes and their electronic structure. We propose that there is a significant mixing of the triplet (S = 1) excited state with the quintet (S= 2) ground state in Mn(III) complexes with porphyrinic ligands, which is even more pronounced for corroles.
Spectrochim Acta A
Mol
Biomol Spectrosc 2002 Apr
PMID:High-frequency and -field electron paramagnetic resonance of high-spin manganese(III) in tetrapyrrole complexes. 1199 60
Photolysis of the ternary system consisting of diethyldithiocarbamate (Et2dtc), diethyldiselenocarbamate (Et2dsc) and copper(II) (1:1:1) has been studied in isobutylmethylketone (IBMK),
toluene
, chloromethane and chloromethane/ROH solutions (chloromethane = CCl4, CHCl3 or CH2Cl2 and ROH = EtOH or i-PrOH). The results obtained by EPR techniques and UV-Vis data indicate that a homolytic Cu-S bond cleavage involving the dithiocarbamate (dtc) ligand appears as the primary photo-process in Cu(Et2dtc)(Et2dsc) photolysis. Further conversion of the primary photoproduct Cu(I)(Et2dsc) is discussed in terms of a specific interaction with the solvent. In chloromethanes and chloromethane/ROH Cu(I)(Et2dsc) is oxidised by the solvent to give the corresponding paramagnetic mixed-ligand Cu(II)(Et2dsc)Cl complex and/or its chloride-bridged and EPR silent dimer Cu2(Et2dsc)2Cl2. The formation of the monomeric species occurs through a co-ordination of the alcohol molecule in the xy plane of the complex. Because of its co-ordination inertness,
toluene
poorly stabilises the primary photoproduct Cu(I)(Et2dsc), thus providing an effective primary recombination process and lower efficiency of Cu(Et2dtc)(Et2dsc) photolysis. The formation of the bis-solvated mixed-ligand complex Cu(II)(Et2dsc)+ in IBMK is also discussed.
Spectrochim Acta A
Mol
Biomol Spectrosc 2002 Apr
PMID:Charge-transfer photochemistry of the ternary complex (dithio-diseleno-carbamato)copper(II). 1199 64
Radiolabelled free radicals were formed by the addition of muonium--a radioactive hydrogen atom with a positive muon as its nucleus--to benzene,
toluene
and benzaldehyde, as sorbed in porous carbon. The activation parameters associated with their reorientational motion were measured using longitudinal-field muon spin relaxation (LF-MuSRx). Two distinct sorbed fractions were detected in each sample, characterised by molecular reorientational activation energies of 5.9/25.8 kJ/mol for benzene, 2.5/5.9 kJ/mol for
toluene
and 2.9/11.5 kJ/mol for benzaldehyde.
Spectrochim Acta A
Mol
Biomol Spectrosc 2002 Apr
PMID:A radiolabelling study of radicals derived from benzene, toluene and benzaldehyde sorbed in model environmental carbon. 1199 69
The transport systems of the first completely sequenced genome of a plant parasite, Xylella fastidiosa, were analyzed. In all, 209 proteins were classified here as constitutive members of transport families; thus, we have identified 69 new transporters in addition to the 140 previously annotated. The analysis lead to several hints on potential ways of controlling the disease it causes on citrus trees. An ADP:ATP translocator, previously found in intracellular parasites only, was found in X. fastidiosa. A P-type ATPase is missing-among the 24 completely sequenced eubacteria to date, only three (including X. fastidiosa) do not have a P-type ATPase, and they are all parasites transmitted by insect vectors. An incomplete phosphotransferase system (PTS) was found, without the permease subunits-we conjecture either that they are among the hypothetical proteins or that the PTS plays a solely metabolic regulatory role. We propose that the Ttg2 ABC system might be an import system eventually involved in glutamate import rather than a
toluene
exporter, as previously annotated. X. fastidiosa exhibits fewer proteins with > or =4 alpha-helical transmembrane spanners than any other completely sequenced prokaryote to date. X. fastidiosa has only 2.7% of all open reading frames identifiable as major transporters, which puts it as the eubacterium having the lowest percentage of open reading frames involved in transport, closer to two archaea, Methanococcus jannaschii (2.4%) and Methanobacterium thermoautotrophicum (2.4%).
Microbiol
Mol
Biol Rev 2002 Jun
PMID:Whole-genome analysis of transporters in the plant pathogen Xylella fastidiosa. 1204 Jan 27
Nearly 9 million workers are exposed to chemical agents associated with occupational asthma, with isocyanates representing the chemical class most responsible. Isocyanate-induced asthma has been difficult to diagnose and control, in part because the biologic mechanisms responsible for the disease and the determinants of exposure have not been well defined. Isocyanate-induced asthma is characterized by airway inflammation, and we hypothesized that inflammation is a prerequisite of isocyanate-induced asthma, with tumor necrosis factor (TNF)-alpha being critical to this process. To explore this hypothesis, wild-type mice, athymic mice, TNF-alpha receptor knockout (TNFR), and anti-TNF-alpha antibody-treated mice were sensitized by subcutaneous injection (20 micro l on Day 1; 5 micro l, Days 4 and 11), and challenged 7 d later by inhalation (100 ppb; Days 20, 22, and 24) with
toluene
diisocyanate (TDI). Airway inflammation, goblet cell metaplasia, epithelial cell damage, and nonspecific airway reactivity to methacholine challenge, measured 24 h following the last challenge, were reduced to baseline levels in TNF-alpha null mice and athymic mice. TNF-alpha deficiency also markedly abrogated TDI-induced Th2 cytokines in airway tissues, indicating a role in the development of Th2 responses. Despite abrogation of all indicators of asthma pathology, TNF-alpha neutralization had no effect on serum IgE levels or IgG-specific TDI antibodies, suggesting the lack of importance of a humoral response in the manifestation of TDI-induced asthma. Instillation studies with fluorescein-conjugated isothiocyanate and TDI suggested that TNF-alpha deficiency also resulted in a significant reduction in the migration of airway dendritic cells to the draining lymph nodes. Taken together, these results suggest that, unlike protein antigens, TNF-alpha has multiple and central roles in TDI-induced asthma, influencing both nonspecific inflammatory processes and specific immune events.
Am J Respir Cell
Mol
Biol 2002 Oct
PMID:Role of tumor necrosis factor in toluene diisocyanate asthma. 1235 72
The car and ant operons originally isolated from Pseudomonas resinovorans strain CA10 contain the genes encoding the carbazole/dioxin-degrading enzymes and anthranilate 1,2-dioxygenase, respectively, and are located on the plasmid pCAR1. The entire nucleotide sequence of pCAR1 was determined to elucidate the mechanism by which the car operon may have been assembled and distributed in nature. pCAR1 is a 199,035-bp circular plasmid, and carries 190 open reading frames. Although the incompatibility group of pCAR1 is unclear, its potential origin for replication, OriP, and Rep and Par proteins appeared to be closely related to those of plasmid pL6.5 isolated from Pseudomonas fluorescens. The potential tellurite-resistance klaABC genes identified in the neighboring region of repA gene were also related to those in IncP plasmid originally identified from pseudomonads. On the other hand, we found genes encoding proteins that showed low but significant homology (20-45% identity) with Trh and Tra proteins from Enterobacteriaceae, which are potentially involved in conjugative transfer of plasmids or genomic island, suggesting that pCAR1 is also a conjugative plasmid. In pCAR1, we found tnpAcCST genes that encoded the proteins showing >70% length-wise identities with those are encoded by the
toluene
/xylene-degrading transposon Tn4651 of TOL plasmid pWW0. Both car and ant degradative operons were found within a 72.8-kb Tn4676 sequence defined by flanking tnpAcC and tnpST genes and bordered by a 46-bp inverted repeat (IR). Within Tn4676 and its flanking region, we found the remnants of numerous mobile genetic elements, such as the duplicated transposase genes that are highly homologous to tnpR of Tn4653 and the multiple candidates of IRs for Tn4676 and Tn4653-like element. We also found distinct regions with high and low G+C contents within Tn4676, which contain an ant operon and car operon, respectively. These results suggested that multiple step assembly could have taken place before the current structure of Tn4676 had been captured.
J
Mol
Biol 2003 Feb 07
PMID:Complete nucleotide sequence of carbazole/dioxin-degrading plasmid pCAR1 in Pseudomonas resinovorans strain CA10 indicates its mosaicity and the presence of large catabolic transposon Tn4676. 1254 88
The synthesis, spectroscopy, and redox-reactivity towards PPh(3) of bis(3,5-di-t-butyl-1,2-benzoquinone 1-oximato)manganese(II), Mn(ox)(2), and its mixed-ligand complexes, Mn(ox)L(x) [L(x)=8-hydroxyquinolinato (L(1)), 2,2'-bipyridine (bpy) (L(2)), 1,10-Phenanthroline (phen) (L(3)) and N-(2-hydroxyphenyl)-3,5-di-t-butylsalicylaldiminato (L(4))] complexes, are presented. While some complexes exhibit solid-state ESR spectra they were ESR-silent in
toluene
or CHCl(3) at 300 K. The reduction of all ESR-silent complexes with an excess of PPh(3), independently from the nature of secondary L(x) ligands, results in the appearance of a six-line hyperfine coupling of 55Mn (I=5/2) (A(Mn)=95-100 G) and a seven-line radical signal, which was assigned to phosphiniminophenoxyl type radicals (g=2.0056-2.0075, A(P)=8. 5 G and A(N)=1.875 G).
Spectrochim Acta A
Mol
Biomol Spectrosc 2003 Apr
PMID:Studies on bis(3,5-di-t-butyl-1,2-benzoquinone 1-oximato)manganese(II) and its mixed-ligand complexes. 1265 83
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