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)

Complement-mediated release of soluble immune complexes and immune precipitates containing DNP-PSA and precipitating or non-precipitating porcine anti-DNP antibodies was studied. A decrease in the average size of soluble immune complexes indicating their fragmentation was observed during incubation in excess human serum, the extent of the complex release was found to be in direct proportion to the time of incubation. The effect was complement-dependent. In the second part of the study, complement-dependent solubilization of the immune precipitates of the precipitating antibody preparation was compared to the solubilization of the precipitates of the non-precipitating antibody formed in the presence of PEG. Although, both types of precipitates activated complement in about the same extent, complexes of non-precipitating antibody were solubilized much slower than those of the precipitating one. As avidity of both antibody preparations to the antigen was high, the observed differences in the rate of the complex solubilization probably reflected differences in the structure of the two types of complexes.
Mol Immunol 1982 Feb
PMID:Complement-mediated fragmentation of soluble and insoluble immune complexes containing porcine anti-DNP antibodies. 709 69

The rate of 1H leads to 3H exchange between water and C(8)H groups of purinic residues in chromatin as well as in optically active and optically inactive compact DNA particles, formed in PEG-containing water-salt solutions was measured. In chromatin the rate of exchange is shown to be about 15% lower as compared to that in the open form of DNA. Assuming the ylid mechanism of exchange the retardation observed may be interpreted as a consequence of screecing of C(8)H groups by proteins of chromatin which hampers the contacts of these groups with OH- ions of the solvent. In optically active compact particles the rate of exchange is shown to be as high as 20% but in optically inactive particles up to 60% as compared to the open form of DNA. This fact indicates the difference of the secondary structure of DNA in these two compact forms. The ratio between the rate constants in guanylic and adenylic residues (kG : kA) in the open form of DNA as well as in chromatin and in optically active compact particles is equal 3.0, whereas the ratios in mononucleotides and in optically inactive particles are equal 1.6 and 2.2, accordingly. Comparison of the 1H leads to 3H exchange kinetic data with literature data on the small-angle X-ray scattering reflexes for optically active and optically inactive compact particles of DNA, suggests that the secondary structure of DNA in chromatin and in optically active compact particles is a highly-ordered one, whereas in optically inactive compact particles of DNA the bases are to a great extent disordered.
Mol Biol (Mosk)
PMID:[Study of conformational differences between DNA composing chromatin and compact particles by the slow 1H--3H exchange method]. 718 20

The conditions (mol. weight of PEG, ionic strength) of formation of double-stranded RNA (dsRNA) compact particles in water-salt solutions, containing poly(ethylene glycol) (PEG) have been determined. It has been shown, that in solutions of mild ionic strength (approximately 0,3) the compact particles of dsRNA are characterized by an intense positive CD-band (lambda 270 nm), but in solutions of high ionic strength (1,0-1,5)--by intense positive or negative CD-bands (lambda 270 nm). The heating of the solutions of a high ionic strength, containing the compact particles with negative CD-bands is accompanied by the change of sign of CD-band. The same effect is observed in the case of decrease of the ionic strength of the solutions. "Melting" of compact particles as revealed by the CD-method occurs prior to the melting of the secondary structure of dsRNA. These data show, that the intense CD-bands reflect the ordered arrangement of the chromophores of polynucleotide chain in compact particles. The reasons of change of the sign of the CD-bands are discussed.
Mol Biol (Mosk)
PMID:[Compact particles of double-stranded polyribonucleotides. I. Conditions for the formation of optically active compact double-stranded RNA particles]. 744 75

Reverse transcriptase (RT) from the human immunodeficiency virus type 1 has been crystallized in four closely related forms, the best of which diffract X-rays to 2.2 A resolution. The RT was crystallized as a complex with a non-nucleoside inhibitor, either nevirapine or a nevirapine analogue. Crystals grew from 6% PEG 3400 buffered at pH 5. These were of space group P2(1)2(1)2(1) with unit cell parameters a = 147 A, b = 112 A, c = 79 A (form A), with one RT heterodimer in the asymmetric unit. Changes in unit cell parameters and degree of crystalline order were observed on soaking pregrown crystals in various solutions, giving three further sets of unit cells. These were a = 143 A, b = 112, A, c = 79 A (form B), a = 141 A, b = 111 A, c = 73 A (form C), a = 143 A, b = 117 A, c = 66.5 A (form D). The last two forms diffract X-rays to 2.2 A resolution. Structure determinations of these latter crystal forms of RT should give a detailed atomic model for this therapeutically important drug target.
J Mol Biol 1994 Sep 30
PMID:Crystals of HIV-1 reverse transcriptase diffracting to 2.2 A resolution. 752 79

The chemotactic cytokine RANTES (Regulated on Activation, Normal T-cell Expressed and Secreted) is a potent chemoattractant and activator of a number of leukocytes, with a molecular mass of 8 kDa. Crystals of this protein have been grown from 100 mM sodium acetate buffer (pH 4.6) containing 200 mM magnesium acetate, with 20% (w/v) PEG 4000 and 6% (v/v) glycerol. The crystals grow as thick rods, which diffract to at least 1.8 A resolution on a rotating anode X-ray source. The crystals belong to space group p2(1)2(1)2(1) with unit cell dimensions a = 95.14 A, b = 57.58 A and c = 24.01 A with alpha = beta = gamma = 90 degrees. The asymmetric unit contains two molecules of the RANTES monomer, with a VM of 2.0 A(3)/Da.
J Mol Biol 1994 Sep 30
PMID:Crystallization and preliminary X-ray diffraction studies of human RANTES. 752 80

Protein synthesis in an aqueous two-phase system is reported here as a novel type of extractive bioconversion. Translation of BMV RNA was studied using either rabbit reticulocyte lysate or wheat-germ extract in aqueous dextran-PEG systems. Both polymers inhibited protein synthesis and the translation system partitioned into both phases. In the rabbit reticulocyte two-phase system, protein synthesis reached 30% of that in free solution, while in wheat-germ extract it was 60% of that in free solution. Protein was found mainly in the dextran (lower) phase but its partitioning was related to the polymer concentration, and molecular weight, as well as the ionic strength of the system. Protein synthesis was highly influenced by PEG concentration, potassium chloride concentration, and dextran molecular weight.
J Mol Recognit
PMID:Study of cell-free protein synthesis in aqueous two-phase systems. 754 Dec 27

Immobilized metal-ion affinity partitioning (IMAP) is shown to be useful as a preliminary screening test and for the separation of different cell populations based upon recognition of the differences in the proteins on cell surfaces. The feasibility of using IMAP to segregate a spectrum of normal human cells (red blood cells, lymphocytes and fibroblasts) from their counterpart pathological cells has been demonstrated. A clear segregation between normal and sickle-cell anemia red blood cells (RBC), or malaria (Plasmodium vivax) infected RBCs was obtained. Further, the partition differences were found to depend on the nature and the concentrations of metal used. Cells from breast cancer and those from the lung adenocarcinoma showed differences in their partition pattern as compared to normal fibroblasts when PEG-IDA-M(II) was added to the phase system. Maximum differences between the three cell populations were observed in the presence of 10% PEG-IDA-Ni(II). Normal lymphocytes and Burkitt's lymphoma cells (Raji and Namalwa cell lines) were shown to partition differently in the presence of PEG-IDA-M(II) in the phase system. Normal lymphocytes could be distinguished from the Burkitt's lymphoma cell lines in all three phases (top, interface and bottom), in the presence of 10% PEG-IDA-Ni(II) in the system. These differences in the partition behavior could mainly be attributed to the density, surface exposure and micro-environment of histidine residues of cell membrane-associated proteins. These data, along with those obtained for normal and pathological human cells show that IMAP could be a simple and versatile tool for the segregation and study of cells.
J Mol Recognit
PMID:Segregation of normal and pathological human red blood cells, lymphocytes and fibroblasts by immobilized metal-ion affinity partitioning. 759 55

The thrombocyte is the avian equivalent of the mammalian blood platelet and is involved in hemostasis through a fibrinogen-mediated process. Although fibrinogen has been implicated as a molecular bridge between activated cells during aggregation, the location of this molecule and its receptor on thrombocytes has not been characterized. Pigeon fibrinogen, isolated from plasma by precipitation with PEG-1000 and purified over Sepharose 4B, was used to study receptor-ligand interaction. Separation of pigeon fibrinogen on SDS-PAGE resulted in three peptides of molecular mass 62, 55, and 47 kDa, which were comparable to those of human fibrinogen. The role of fibrinogen and its receptor in thrombocyte function was established by turbidimetric aggregation using thrombin as an agonist under conditions requiring Ca2+ and fibrinogen. Maximum response occurred using 3 mM Ca2+ and 100 micrograms/ml fibrinogen. Fibrinogen-dependent aggregation was inhibited by an anti-GPIIb antibody, verifying a role for fibrinogen receptors in thrombocyte function. Fibrinogen-gold conjugates were used to describe receptor and ligand localization on aggregated cells. Computer reconstruction was used to verify relocalization of fibrinogen receptors following activation. Fibrinogen distribution changed from a dispersed state in preactivated cells to focal localization at points of cell contact and along pseudopods following activation. This selective positioning of fibrinogen suggests that a functional relocalization of the receptor occurs upon thrombocyte activation, and this relocation facilitates the role of fibrinogen as a molecular bridge. These studies establish similarities between the avian and the human systems and document the conserved nature of the hemostatic process.
Exp Mol Pathol 1994 Dec
PMID:Localization of fibrinogen during aggregation of avian thrombocytes. 760 Dec 70

The crystal structure of desulforedoxin from Desulfovibrio gigas, a new homo-dimeric (2 x 36 amino acids) non-heme iron protein, has been solved by the SIRAS method using the indium-substituted protein as the single derivative. The structure was refined to a crystallographic R-factor of 16.9% at 1.8 A resolution. Native desulforedoxin crystals were grown from either PEG 4K or lithium sulfate, with cell constants a = b = 42.18 A, c = 72.22 A (for crystals grown from PEG 4K), and they belong to space group P3(2)21. The indium-substituted protein crystallized isomorphously under the same conditions. The 2-fold symmetric dimer is firmly hydrogen bonded and folds as an incomplete beta-barrel with the two iron centers placed on opposite poles of the molecule. Each iron atom is coordinated to four cysteinyl residues in a distorted tetrahedral arrangement. Both iron atoms are 16 A apart but connected across the 2-fold axis by 14 covalent bonds along the polypeptide chain plus two hydrogen bonds. Desulforedoxin and rubredoxin share some structural features but show significant differences in terms of metal environment and water structure, which account for the known spectroscopic differences between rubredoxin and desulforedoxin.
J Mol Biol 1995 Sep 01
PMID:Crystal structure of desulforedoxin from Desulfovibrio gigas determined at 1.8 A resolution: a novel non-heme iron protein structure. 766 20

Diffusion of the fluorescent membrane probe, Dil-C16 (3), from labelled to unlabelled human erythrocytes has been employed to monitor hemi-fusion (membrane fusion) in monolayers of cells exposed to poly(ethylene glycol) (PEG). Diffusion of the cytoplasmic probe, 6-carboxyfluorescein, was used similarly to monitor cell fusion (cytoplasmic mixing). Hemi-fusion, which is normally seen when erythrocytes are exposed to dehydrating concentrations of commercial PEG 6000, did not occur when the PEG was pretreated with Chelex 100 resin to remove metal ions. Cytoplasmic mixing, which is normally observed when the dehydrated erythrocytes are substantially rehydrated, also failed to occur when both PEG 6000 and the rehydrating buffer had been treated with Chelex 100. The re-addition to Chelex-treated PEG of components removed by the resin, and the addition of 10 mu mM concentrations of La3+ or Al3+, restored its ability to induce hemi-fusion and cell fusion. Higher concentrations of several other metals, including Ca2+, were also effective. These observations show that metal ions are required for hemi-fusion with erythrocytes in the presence of PEG, and that dehydration alone is insufficient to induce hemi-fusion. Phosphatidylserine was apparently not accessible in erythrocytes treated with PEG 6000 until the cells were rehydrated. This indicates that metal ions do not assist the hemi-fusion of erythrocytes by forming trans complexes with surface phosphatidylserine when the cells are dehydrated by PEG.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Membr Biol
PMID:Interactions between metal ions and poly(ethylene glycol) in the fusion of human erythrocytes. 774 82


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