Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1H-NMR spectroscopy showed that the extracellular heterpolysaccharides (EPS) from derivatives of Rhizobium leguminosarum bv. trifolii ANU843 altered in pSym nod composition or function (transposon insertions, deletion of pSym, induction by flavone, and introduction of cloned pSym nod regions from ANU843 and R. l. bv. viciae 248 on recombinant plasmids into the pSym-cured background of ANU843) differed only in 3-hydroxybutyrate stoichiometry per octaglycosyl unit. This change in EPS was likely to be an indirect effect of altered growth during expression of pSym nod genes in the presence of the flavone. No modifications were found in EPS made by R. l. bv. phaseoli 8002 when its resident pSym was deleted or replaced with pSym from R. l. bv. viciae 248, or with a derivative of this pSym lacking the host-specific nodulation genes nodFELMNTO. Thus, although certain O-acyl noncarbohydrate substitutions in EPS are affected by pSym nod genes (including the ones that determine host range) in certain backgrounds of R. leguminosarum, this change does not occur universally among all strains of R. leguminosarum. We conclude that the structure of the acidic EPS does not control host-specific nodulation of white clover, hairy vetch, and beans for the strains of R. leguminosarum tested here.
Mol Plant Microbe Interact
PMID:Evaluation of acidic heteropolysaccharide structures in Rhizobium leguminosarum biovars altered in nodulation genes and host range. 147 3

The behaviour of sodium transport systems across the cell membrane has been poorly investigated in elderly hypertension. Sodium efflux driven by Na+/K+/Cl-cotransport activity was therefore investigated (using a novel NMR-spectroscopy method) in 5 elderly hypertensive males (mean age 78 +/- 5 years) and 5 normotensive controls (mean age 79 +/- 3 years). In order to exclude any change in cotransport activity secondary to metabolic abnormalities, both patients and controls were non-obese and had normal glucose and lipid metabolisms. The Na+/K+/Cl-cotransport evaluation was performed after three months of pharmacological wash-out, under a diet containing 120 mEq of Na+/day. The resulting data showed that Na+ efflux due to outward Na+/K+/Cl-cotransport was higher in hypertensive group than in the normotensive one (0.50 +/- 0.10 mmol Na+/l cells/hr. vs 0.33 +/- 0.03 mmol Na+/l cells/hr., respectively, p < 0.05). Intracellular Na+ content was similar in both groups. At variance with previous data from the literature, our findings indicate that the Na+/K+/Cl-cotransport activity is elevated in elderly hypertensives.
Cell Mol Biol (Noisy-le-grand) 1992 Dec
PMID:23Na NMR evaluation of human erythrocytes Na+/K+/CL-cotransport. A study in elderly hypertensives. 147 4

A NMR method based on the analysis of the transverse magnetization decay curve of water protons, was employed to study the hydration process of commercial cowpeas. In order to investigate the role of the different anatomical parts of the seeds, hilum and micropyle, or alternatively seed coat, were inhibited by a water resistant epoxy resin. The kinetic constant for the hydration of the different sets of beans was measured.
Cell Mol Biol (Noisy-le-grand)
PMID:NMR study of seed hydration: the role of the seed anatomical structures in water uptake of soaked cowpeas. 148 18

Human respiratory mucin glycoproteins from patients with cystic fibrosis were purified and oligosaccharide chains were released by treatment with alkaline borohydride. A neutral oligosaccharide alditol fraction was isolated from mucin obtained from a patient with A blood group determinant by chromatography on DEAE-cellulose and individual oligosaccharide chains were then isolated by gel filtration on BioGel P-6 columns and high performance liquid chromatography with gradient and isocratic solvent systems. The structures of the purified oligosaccharides were determined by methylation analysis, sequential glycosidase digestion and 'H-NMR spectroscopy. The amount of each chain was determined by compositional analysis. A wide array of discrete branched oligosaccharide structures that contain from 3 to 22 sugar residues were found. Many of the oligosaccharides are related and appear to be precursors of larger chains. The predominant branched oligosaccharides which accumulate contain terminal blood group H (Fuc alpha 2Ga1 beta 4) or blood group A (Fuc alpha 2(Ga1NAc alpha 3) (Ga1 beta 4) determinants which stop further branching and chain elongation. The elongation of oligosaccharide chains in respiratory mucins occurs on the beta 3-linked G1cNAc at branch points, whereas the beta 6-linked G1cNAc residue ultimately forms short side chains with a Fuc alpha 2(Ga1NAc alpha 3) Ga1 beta 4 G1cNAc beta 6 structure in individuals with A blood group determinant. The results obtained in the current studies further suggest that even higher molecular weight oligosaccharide chains with analogous branched structures are present in some human respiratory mucin glycoproteins. Increasing numbers of the repeating sequence shown in the oligosaccharide below is present in the higher molecular weight chains. [formula: see text] This data in conjunction with our earlier observations on the extensive branching of these oligosaccharide chains helps to define and explain the enormous range of oligosaccharide structures found in human and swine respiratory mucin glycoproteins. Comparison of the relative concentrations of each oligosaccharide chain suggest that these oligosaccharides represent variations of a common branched core structure which may be terminated by the addition of alpha 2-linked fucose to the beta 3/4 linked galactose residue at each branch point. These chains accumulate and are found in the highest concentrations in these respiratory mucins.
Mol Cell Biochem 1992 Dec 02
PMID:Quantitation and structures of oligosaccharide chains in human trachea mucin glycoproteins. 148 58

Spatial structures of proteolytic segment A (sA) of bacterioopsin of Halobacterium halobium (residues 1-36) solubilized in the mixture of methanol-chloroform (1:1), 0.1 M LiClO4 or in perdeuteriated sodium dodecyl sulfate (SDS) micelles, were determined by 2D 1H-NMR techniques. Most of the resonances in 1H-NMR spectra of fragment A were assigned using DQF-COSY, TOCSY and NOESY spectra. Deuterium exchange rates for amide protons were measured in series of NOESY spectra. 324 and 400 NOESY cross-peak volumes were measured in NOESY spectra of sA in mixture of organic solvents and SDS micelles, respectively. The sA structure was determined by local structure analysis, distance geometry calculation with program DIANA and systematic search for energetically allowed side chain rotamers consistent with NOESY cross-peak volumes. The structures of sA are similar in both milieus. These structures have the right-handed alpha-helical region from Pro-8 to Met-32 with root mean square deviation (RMSD) of 0.25 A between back bone heavy atoms and fit well with Pro-8 to Met-32 alpha-helical region in electron cryo-microscopy (ECM) model of bacteriorhodopsin [4]. The C-terminal region Gly-33-Asp-36 is disordered in both milieus, while N-terminal region Ala-2-Gly-6 in organic solvents has a fixed structure (RMSD of 0.25 A) stabilized by the Thr-5 NH...O=C Gln-3 and Ile-4 NH...O = C Ala-2 hydrogen bonds. This region of sA in SDS micelles has disordered structure with RMSD of 1.44 A for back bone heavy atoms. Torsion angles chi 1 of sA were unequivocally determined for 72% of side chains in the alpha-helical region and are identical in both milieus.
Mol Biol (Mosk)
PMID:[Spatial structure of (1-36)bacterioopsin solubilized in a methanol-chloroform mixture with sodium dodecylsulfate micelles]. 149 81

The structure of the glycoprotein hormones (LH, CG, FSH, and TSH) and their mechanism of receptor recognition are problems of long-standing interest and speculation. Here we describe the two-dimensional [1H]nuclear magnetic resonance ([1H]NMR) analysis of a linear peptide model for the intercysteine sequence (38-57) from the beta-subunit of human (h) LH. This sequence contains functional determinants for receptor binding and postreceptor activation and is predicted by computer-based modeling to fold as a compact minidomain containing a central amphipathic helix. To test this prediction, an Arg-extended disulfide-free (38-57) analog of enhanced solubility was prepared for complementary circular-dichroic and two-dimensional NMR studies. The linear peptide retains ovarian membrane receptor-binding activity. Although the peptide is not highly structured in aqueous solution, circular-dichroic analysis shows partial alpha-helix formation in a lipophilic medium (50% trifluoroethanol). Complete sequential assignment is obtained in 50% trifluoroethanol based on homonuclear and [15N]edited heteronuclear NMR methods. alpha-Helix-related (i,i + 3) connectivities are observed by nuclear-Overhauser effect spectroscopy that define an amphipathic alpha-helical segment (residues 41-48). Additional long range nuclear-Overhauser effects are observed in the C-terminal region that are consistent with beta-turns involving one or more proline residues; these may serve to reverse the direction of the peptide chain. A nuclear-Overhauser effect contact is identified between residues 38 and 55 at opposite ends of the linear sequence, suggesting that a loop configuration is significantly populated in this solvent system. These results, taken together, characterize elements of ordered structure in the 38-57 peptide, which appear to be distinguishing features of hLH (and the homologous region of hCG). We propose that the structure of this peptide provides a model for the structure of the corresponding region of native hLH in the hormone-receptor complex.
Mol Endocrinol 1992 Jun
PMID:Structure of a receptor-binding fragment from human luteinizing hormone beta-subunit determined by [1H]- and [15N]nuclear magnetic resonance spectroscopy. 149 92

We examined the effects of cholesterol on the membrane-disordering action of ethanol by using deuterium nuclear magnetic resonance (2H-NMR) and fluorescence spectroscopy. Specifically, the effects of ethanol were measured on the 2H-NMR spectra of di(perdeuteropalmitoyl)phosphatidylcholine (DPPC-d62) and on the steady-state emission anisotropy of diphenylhexatriene (DPH) incorporated into hydrated egg phosphatidylcholine (eggPC)/cholesterol dispersions. Analysis of the 2H-NMR spectra of DPPC-d62 incorporated into eggPC liposomes showed that the addition of cholesterol up to 30 mol% enhanced the ability of ethanol to disorder methylene groups all along the phospholipid acyl chains. This effect was somewhat greater toward the terminal methyl groups. However, above 30 mol% cholesterol, the bilayer-disordering action of ethanol on both the upper and lower portions of the acyl chains decreased to an apparent constant change up to the highest cholesterol content examined (50 mol%). Analysis of the fluorescence anisotropy of DPH, on the other hand, suggested that cholesterol attenuated the ability of ethanol to disorder the bilayers, which is in agreement with a previous EPR study [Chin and Goldstein, Mol Pharmacol 19: 425-431, 1981]. Re-analysis of our previous fluorescence anisotropy results with DPH incorporated into dispersions of brain-lipid extracts as a percent change [Johnson et al., Mol Pharmacol 15: 739-746, 1979] indicated that the chemical composition of the lipid bilayers also affects the apparent ability of cholesterol to modulate the membrane-disordering action of ethanol, because the addition of cholesterol to brain-lipid extracts had no significant effect on the membrane-disordering action of ethanol. Given the greater likelihood that the 2H-NMR probes accurately monitor bulk phospholipid properties, some caution is required in the analysis of the membrane-disordering actions of drugs using EPR and fluorescence spectroscopy.
 ...
PMID:A deuterium NMR and steady-state fluorescence anisotropy study of the effects of cholesterol on the lipid membrane-disordering actions of ethanol. 151 Jul 24

The spatial structure of a synthetic 32-residue polypeptide, an analog of the membrane-spanning segment B (residues 34-65) of bacterioopsin of Halobacterium halobium, incorporated into perdeuterated sodium dodecyl sulfate micelles, was determined from 1H NMR data. The structure determination included the following steps: (1) local structure analysis; (2) structure calculations using the distance geometry program DIANA; (3) systematic search for energetically allowed side-chain rotamers consistent with NOESY cross-peak volumes; (4) random generation of peptide conformations in allowed conformational space. The obtained structure has a right-handed alpha-helical region from Lys41 to Leu62 with a kink of 27 degrees at Pro50. The C-cap Gly63 adopts a conformation with phi = 87 +/- 6 degrees, psi = 43 +/- 10 degrees typical to a left-handed helix. The N-terminal part (residues 34-40) is exposed to the aqueous phase and lacks an ordered conformation. The secondary structure of segment B in micelles is consistent with the high-resolution electron cryomicroscopy model of bacteriorhodopsin (Henderson et al. (1990) J. Mol. Biol., 213, 899-929).
J Biomol NMR 1992 Jul
PMID:Spatial structure of (34-65)bacterioopsin polypeptide in SDS micelles determined from nuclear magnetic resonance data. 151 Dec 36

We have created a bacterial expression-export system and have used it to express (14 mg l-1) the variable region fragment (Fv) of an anti-digoxin antibody (26-10) in Escherichia coli. The expression-export plasmid contains a T7 promoter and the E. coli signal sequences ompA [Movva et al., J. biol. Chem. 255, 27-29 (1980)] and phoA [Inouye et al., J. Bacteriol. 149, 434-439 (1982)] fused to heavy chain (VH) and light chain (VL) variable region sequences to generate an artificial cistron. The 26-10 Fv protein made using this system was soluble, unlike many other expression systems which produce insoluble proteins in the form of inclusion bodies. The 26-10 VH and VL proteins were cleaved at their mature N-termini and exported into the bacterial periplasm where they could be easily extracted and affinity purified on ouabain-Sepharose. 26-10 Fv bound to digoxin with similar affinity and specificity as the whole 26-10 antibody (Ka for Fv, 1.3 x 10(9) M-1, Ka for IgG, 7 x 10(9) M-1). 26-10 Fv appears to be remarkably stable in comparison with other Fv fragments. The half-life for chain dissociation of 26-10 Fv was 48 hr compared to the reported 1.5 hr half-life of McPC603 Fv. We present the proton NMR spectra of the 26-10 Fv as preliminary evidence that this expression-export system can be used to facilitate the analysis of the solution structure of 26-10 Fv by NMR.
Mol Immunol 1992 Oct
PMID:Production of stable anti-digoxin Fv in Escherichia coli. 152 94

Important mammalian defensive functions such as phagocytosis are triggered in leukocytes by the interaction of the Fc region of IgG with cell surface receptors (Fc gamma R). The CH2 domain of IgG has been implicated previously as the site of interaction with human and mouse Fc gamma R. This domain was mapped for interaction with mouse Fc gamma R11 expressed by the macrophage-like cell line P388D1, using two panels of a total of 32 site-directed mutants of mouse IgG2b and chimeric human IgG3 monoclonal antibodies. Two potential binding sites have been identified: one in or within the vicinity of the lower hinge site on IgG for human Fc gamma R1, and one within the binding site on IgG for Clq. The three mutant IgGs (Gly 237----Ala, Asn 297----Ala, and Glu 318----Ala) which do not interact in complexed form also fail to bind as monomers. A 1H NMR study of the three non-binding monomeric mutants suggests that the mutations are largely site-specific, indicating that IgG interacts with mouse Fc gamma R11 at two regions within the CH2 domain. This interaction dictates phagocytosis mediated by Fc gamma R11 of the P388D1 cell line.
Mol Immunol 1992 Jan
PMID:Multiple binding sites on the CH2 domain of IgG for mouse Fc gamma R11. 153 Sep 84


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>