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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A segment of the exotoxin A gene of Pseudomonas aeruginosa, coding for the N-terminal end of domain I and domain II of the toxin (ETA), was genetically fused to the diphtheria toxin gene of Corynebacterium diphtheriae, coding for the N-terminal end of A fragment of diphtheria toxin (DT). The resulting hybrid protein (termed CED1) was produced in large amounts and exported to the periplasm in Escherichia coli. This chimaeric protein reacted with both anti-ETA and anti-DT antisera. Furthermore, the chimaeric protein displayed ADP-ribosylation activity and exhibited cytotoxicity to mouse 3T6 fibroblasts. These results demonstrated that the chimaeric protein is cytotoxic, and that the toxic potential of DTA can be selectively internalized and translocated via domains I and II of exotoxin A, which are thus sufficient to direct and translocate an enzymatically active heterologous polypeptide segment into the cytosol of sensitive cells.
Mol Microbiol 1992 May
PMID:Cytotoxic activity of a recombinant chimaeric protein between Pseudomonas aeruginosa exotoxin A and Corynebacterium diphtheriae diphtheria toxin. 164 Aug 30

After reaching early endosomes by receptor-mediated endocytosis, diphtheria toxin (DT) molecules have two possible fates. A large pool enters the degradative pathway whereas a few molecules become cytotoxic by translocating their catalytic fragment A (DTA) into the cytosol. Impairment of DT degradation by microtubule depolymerization does not block DT cytotoxicity. Therefore, DTA membrane translocation into the cytosol occurs from an endocytic compartment located upstream of late endosomes. Comparisons between early endosomes and endocytic carrier vesicles in a cell-free translocation assay have demonstrated that early endosomes are the earliest endocytic compartment from which DTA translocates. DTA translocation is ATP-dependent, requires early endosomal acidification, and is increased by the addition of cytosol. Cytosol-dependent DTA translocation is GTP gamma S-insensitive but is blocked by anti-beta COP antibodies.
Mol Microbiol 1997 Feb
PMID:Membrane translocation of diphtheria toxin fragment A exploits early to late endosome trafficking machinery. 904 79

The Escherichia coli iron transport system via ferrichrome belongs to the group of ATP-dependent transporters that are widely distributed in prokaryotes and eukaryotes. Transport across the cytoplasmic membrane is mediated by three proteins: FhuD in the periplasm, FhuB in the cytoplasmic membrane and FhuC (ATPase) associated with the inside of the cytoplasmic membrane. Interaction of FhuD with FhuB was studied in vitro with biotinylated synthetic 10 residue and 20-24 residue peptides of FhuB by determining the activity of beta-galactosidase linked to the peptides via streptavidin. Peptides identical in sequence to only one of the four periplasmic loops (loop 2), predicted by a transmembrane model of FhuB, and peptides representing a transmembrane segment and part of the adjacent cytoplasmic loop 7 of FhuB bound to FhuD. Decapeptides were transferred into the periplasm of cells through a FhuA deletion derivative that forms permanently open channels three times as large as the porins in the outer membrane. FhuB peptides that bound to FhuD inhibited ferrichrome transport, while peptides that did not bind to FhuD did not affect transport. These data led us to propose that the periplasmic FhuD interacts with a transmembrane region and the cytoplasmic segment 7 of FhuB. The transmembrane region may be part of a pore through which a portion of FhuD inserts into the cytoplasmic membrane during transport. The cytoplasmic segment 7 of FhuB contains the conserved amino acid sequence EAA...G (in FhuB DTA ...G) found in ABC transporters, which is predicted to interact with the cytoplasmic FhuC ATPase. Triggering of ATP hydrolysis by substrate-loaded FhuD may occur by physical interaction between FhuD and FhuC, which bind close to each other on loop 7. Although FhuB consists of two homologous halves, FhuB(N) and FhuB(C), the sites identified for FhuD-mediated ferrichrome transport are asymmetrically arranged.
Mol Microbiol 1997 Dec
PMID:ATP-dependent ferric hydroxamate transport system in Escherichia coli: periplasmic FhuD interacts with a periplasmic and with a transmembrane/cytoplasmic region of the integral membrane protein FhuB, as revealed by competitive peptide mapping. 942 46

Anthrax lethal toxin is a mixture of protective antigen (PA, 735 AA) and lethal factor (LF, 776 AA). Earlier studies have shown that 254 residues of lethal factor are sufficient for PA binding to cause internalization (Arora N and Leppla SH, J Biol Chem 268: 3334-3342, 1993). The present study was undertaken to determine residues which are important for binding of LF to PA. LF modification with diethyl pyrocarbonate (DEPC, modifies histidine residue primarily) results in the loss of binding and toxicity in mammalian cells. There are nine histidine residues in the binding domain. To locate the important residue(s), site-directed mutagenesis of these histidines were performed by recombinant methods. Replacement of His42 with Gly42 destablizes the protein and hence it could not be purified. His35 when mutagenized to Gly35 (mLF-DTA) diminishes the toxicity by 20 fold. Time dependent studies show that binding of mLF-DTA was reduced at shorter incubations and longer incubations taper off this difference. Gel shift assay suggested 8-10% less binding of mLF-DTA as compared to LF-DTA. In conclusion His35 is important for binding and His42 is critical and confers proper conformation for LF binding to PA.
Mol Cell Biochem 1997 Dec
PMID:Site directed mutagenesis of histidine residues in anthrax toxin lethal factor binding domain reduces toxicity. 945 Jun 39

The complexes of 2-thiobarbituric acid with Fe(II), Fe(III), Co(II), Cu(II), Zn(II) and Cd(II) have been isolated and characterized on the basis of elemental analyses, molar conductance, magnetic moment and spectral studies. The thermal decomposition of the metal complexes was studied by TG and DTA techniques. The kinetic parameters namely, activation energy, entropy of activation and the reaction orders were estimated.
Spectrochim Acta A Mol Biomol Spectrosc 2000 Jun
PMID:Spectral and thermal studies of thiobarbituric acid complexes. 1088 28

FTIR and Infrared emission spectroscopy (IES) has been used to characterise the Uley (Australian) and Garfield nontronites. These clay minerals are characterised by a strong emission band at 3570 cm(-1) attributed to the FeFeOH unit. Dehydroxylation is followed by the loss of intensity of this band as a function of temperature. Dehydroxylation is also followed by the loss of intensity of the FeFeOH deformation vibration at 843 cm(-1). IES shows that the dehydroxylation occurs as a continuous process in comparison to DTA/TGA studies where the dehydroxylation occurs abruptly at 425 degrees C. Water in these high iron bearing smectites have been observed through the stretching mode at 3430 cm(-1) and the bending mode at 1630 cm(-1). Different types of water are identified in the nontronite structure by the analysis of the band profile in the 1590-1680 cm(-1) region. Low frequency vibrations show that the Uley green nontronite is similar to the Garfield nontronite. The brown Uley nontronite is closer to the Hohen-Hagen nontronite. The Uley nontronites may, therefore, be used spectroscopically to replace other nontronites as a reference clay mineral.
Spectrochim Acta A Mol Biomol Spectrosc 2002 Jul
PMID:The Garfield and Uley nontronites--an infrared spectroscopic comparison. 1216 87

The inclusion coordinated compound fluorescence of p-hydroxyphenolacetamide (PHPA) with beta-cyclodextrin was studied and a high sensitive analytical method to determine the content of PHPA was established based on the increased fluorescence intensity of the coordinated compounds in Britton-Robinson buffer solution (pH 7). The wavelength of the excited emission are 282 and 310 nm, respectively. The enhanced coordinated compounds fluorescence intensity is proportional to the concentration of PHPA in the range 0.030-11.0 mg/l. The relative standard deviation (R.S.D.) were within 0.66-4.2%. Correlation coefficient and inclusion binding constant Kf are obtained within 0.9950-0.9996 and 4.67 x 10(2), respectively. Meanwhile, a linear increase of the resonance light scattering (RLS) with the inclusion coordinated compounds concentration was noticed at a synchronous wavelength of 584 nm. The forming reasons of inclusion coordinated compounds were investigated. The 1:1 molar ratio composition of inclusion compound was measured with DTA and elemental analysis. The method is simple, rapid and has a good reproducibility. The method was used for determination of PHPA in an artificial sample with satisfactory results.
Spectrochim Acta A Mol Biomol Spectrosc 2002 Oct
PMID:The fluorescence study of the inclusion coordinated compound of beta-cyclodextrin and p-hydroxyphenolacetamide and its analytical applications. 1239 49

[M(H2L)2](A)2.yH2O (where H2L: neutral piroxicam (Pir), A: Cl- in case of Ni(II) or acetate anion in case of Cu(II) and Zn(II) ions and y=0-2.5) and [M(H2L)3](A)z.yH2O (A: SO4(2-) in case of Fe(II) ion (z=1) or Cl(-) in case of Fe(III) (z=3) and Co(II) ions (z=2) and y=1-4) chelates are prepared and characterized using elemental analyses, IR, magnetic and electronic reflectance measurements, mass spectra and thermal analyses. IR spectra reveal that Pir behaves a neutral bidentate ligand coordinated to the metal ions through the pyridyl-N and carbonyl-O of the amide moiety. The reflectance and magnetic moment measurements reveal that these chelates have tetrahedral, square planar and octahedral geometrical structures. Mass spectra and thermal analyses are also used to confirm the proposed formulae and the possible fragments resulted from fragmentation of Pir and its chelates. The thermal behaviour of the chelates (TGA and DTA) are discussed in detail and the thermal stability of the anhydrous chelates follow the order Ni(II) congruent with Cu(II) Fe(II)<Zn(II)<Fe(III)<Co(II) chelates. The water molecules are removed in the first step while the Pir molecule is removed in the second and subsequent steps. X-ray powder diffraction was also used as a confirmatory tool to elucidate the crystallinity of the chelates.
Spectrochim Acta A Mol Biomol Spectrosc 2004 Oct
PMID:Structure investigation, spectral, thermal, X-ray and mass characterization of piroxicam and its metal complexes. 1535 Sep 21

A semiorganic nonlinear optical material, lithium bis-L-malato borate (LBMB) (molecular formula C8H8BLiO10), has been synthesized, and single crystals grown from an aqueous solution, by the method of slow evaporation at 30 degrees C. Crystals of size up to 7 mm x 3 mm x 2 mm were harvested and characterized by powder and single crystal X-ray diffraction and Fourier transform infrared techniques to confirm the identity of the compound formed. The TG-DTA results establish the good thermal stability of the material. The UV-Vis-NIR spectral study reveals that the material has a wide transparency window (230-1500 nm) with a lower cutoff at 230 nm. Kurtz powder test with a Nd:YAG laser indicates the production of SHG output.
Spectrochim Acta A Mol Biomol Spectrosc 2005 Jun
PMID:X-ray diffraction, spectroscopic and thermal studies on a potential semiorganic NLO material: lithium bis-L-malato borate. 1586 47

The study of some transition metals (M) and amoxicillin trihydrate (ACT) ligand complexes (M-ACT) that formed in solution involved the spectrophotometric determination of stoichiometric ratios and their stability constants and these ratios were found to be M:ACT = 1:1, 1:2 and 2:1 in some instances. The calculated stability constants of these chelates, under selected optimum conditions, using molar ratio method have values ranging from K(f) = 10(7) to 10(14). These data were confirmed by calculations of their free energy of formation deltaG, which corresponded to their high stabilities. The separated solid complexes were studied using elemental analyses, IR, reflectance spectra, magnetic measurements, mass spectra and thermal analyses (TGA and DTA). The proposed general formulae of these complexes were found to be ML(H2O)w(H2O)x(OH)y(Cl)2, where M = Fe(II), Co(III), w = 0, x = 2, y = 1, z = 0; M = Co(II), w = 0, x = 1, y = 0, z = 1; M = Fe(III), w = 0, x = 1, y = 2, z = 0; M = Ni(II), Cu(II) and Zn(II), w = 2, x = 0, y = 1, z = 0, where w = water of crystallization, x = coordinated water, y = coordinated OH(-) and z = Cl- in the outer sphere of the complex. The IR spectra show a shift of nu(NH) (2968 cm(-1)) to 2984-2999 cm(-1) of imino group of the ligand ACT and the absence of nu(CO) (beta-lactame) band at 1774 cm(-1) and the appearance of the band at 1605-1523 cm(-1) in all complexes suggest that 6,7-enolization takes place before coordination of the ligand to the metal ions. The bands of M-N (at 625-520 cm(-1)) and of M-O (at 889-7550 cm(-1)) proved the bond of N (of amino and imino groups) and O of C-O group of the ligand to the metal ions. The reflectance spectra and room temperature magnetic measurements refer to octahedral complexes of Fe(II) and Fe(III); square planner form of Co(II), reduced Co(III), Ni(II) and Cu(II)-ACT complexes but tetrahedral form of Zn-ACT complex. The thermal degradation of these complexes is confirmed by their mass spectral fragmentation. These data confirmed the proposed structural and general formulae of these complexes.
Spectrochim Acta A Mol Biomol Spectrosc 2005 Jul
PMID:Synthesis and structure investigation of the antibiotic amoxicillin complexes of d-block elements. 1591 16


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