Preparation of rare earth ion induced conformation-specific anti-calmodulin monoclonal antibody

Monoclonal antibody technique was employed to detect the conformational change of calmodulin induced by metal ions. Bovine calmodulin was firstly modified by 2,4-dinitrofluorobenzene to improve its immunogenicity, then, the derived protein was saturated with trivalent europium ions and injected to Balb/c mice as antigen. After four times of immunization, a corresponding antibody was detected and its titer in serum was determined as 1 : 12 000. By fusing of the spleen cells with hybridoma cells, a europium induced conformation-specific anti-calmodulin monoclonal antibody cell strain named as 2C3 was produced successfully. The molecular recognition ability of antibody to apocalmodulin and holocalmodulin showed a significant difference, indicating that this antibody could be applied to the studies of different effects of metal ions on the conformational change of calmodulin and its interaction with target molecules.

Preparation of europium induced conformation-specific anti-calmodulin monoclonal antibody

Monoclonal antibody technique was employed to detect the conformational difference of CaM induced by metal ions. A trivalent europium ion induced conformation-specific anti-calmodulin monoclonal antibody was successfully prepared with europium-saturated calmodulin as antigen.

Oxythiamine hexafluorophosphate monohydrate, a thiamine antagonist with the same conformation as thiamine

In the title compound, 3-[(3,4-dihydro-2-methyl-4-oxopyrimidin-5-yl)methyl]-5-(2-hydroxyethyl)-4-methylthiazolium hexafluorophosphate monohydrate, C12H16N3O2S+. PF6-.H2O, oxythiamine is a monovalent cation with a neutral oxopyrimidine ring. The molecule assumes the F conformation, which is a common form for thiamine but which is substantially different from the unusual V conformation found in the chloride and hydrochloride salts of oxythiamine. The anion-bridging interaction, C-H . . . anion . . . pyrimidine, is emphasized as being important for stabilization of the F conformation.

Effect of configuration and conformation on the spin multiplicity in xylylene type biradicals

The singlet-triplet splitting energy gap DeltaE(S.T) = E-S - E-T is calculated for the ortho-, meta-, and para-xylylenes and their heteroatomic analogous by means of AM1-CI approach. It is shown that when the radical centers R-.(R-.=H2C.-,H2N.+- or HN.-) are twisted sufficiently Tar out of conjugation with the benzene ring, DeltaE(S.T) tends to zero or is negative, i.e, ortho-, meta-, and para-phenylenes turn into weak ferromagnetic or antiferromagnetic coupling unit, while they are strong ferromagnetic (meta-isomers) or antiferromagnetic (ortho-, para-isomers) coupling units under planar conformation. It is suggested that serious twisted conformation is not recommended candidate for the design of novel high-spin molecules with stable high-spin ground states by ortho- or para-phenylene coupling unit.

Conformation transformation of syndiotactic polypropylene induced by stretching and annealing

Conformation transformation of syndiotactic polypropylene(sPP) induced by stretching and annealing processes has been investigated by WAXD, IR and DSC, The results indicate that not only the quenched samples but also the isothermally crystallized samples can form the crystals with all-trans conformation by means of uniaxially stretching at room temperature. The all-trans conformation crystals are of metastability, which can transform to stable crystals with (TTGG)(2) helical conformation at higher annealing temperatures.

Structure and Conformation of 2,3,6, 7,10,11-hexakispentyloxytriphenylene by TEM and Computer Simulation

Experimental electron diffraction patterns and high resolution images were used to determine the space group and unit cell dimensions of 2,3,6,7,10,11-hexakispentyloxytriphenylene. Subsequently the molecular conformation was calculated by energy minimized package in Cerius2. Using this method, we got the HPT crystal structure: space group: P6/mmm; lattice type: hexogonal; the lattice parameters are a = b = 20.3 angstrom, c = 3.52 angstrom, = = 90 degrees, = 120 degrees. The core of HPT is not perpendicular to the column. The angle between a axis and HPT core plane is 9 degrees which cannot be seen in b-c projection. The simulated ED patterns and HREM images are good agreement with the experimental ED patterns and HREM images.

Chain conformation of a high-performance polyimide in organic solution

An organo-soluble polyimide based on 1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride (HQDPA) and 2,2'dimethyl-4,4'-methylene dianiline (DMMDA), was synthesized via two-step polycondensation accompanied by chemical imidization. Five fractions were prepared by fractionation. The dilute solutions of the fractions were studied by LLS (Laser Light Scattering) and the intrinsic viscosities of the fractions were measured. The unperturbed dimension was determined by the intrinsic viscosity with the Stockmayer-Fox equation. The results indicate that the polyimide in this study has a flexible chain conformation in chloroform and N,N-dimethyl acetamide (DMAc). However, the degree of chain expansion differs in different solvents. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

RELATIONSHIP BETWEEN CONFORMATION OF TASTE COMPOUNDS AND THEIR ACTIVITIES

The conformation analysis and study on structure-taste relation-ships of 4 taste compounds have been performed, the results reveal that the sweetnees will decrease with the increase of the specific dihedral angle O-1-C-2-C-3-C-4, and the mechanism was intepreted.

EFFECTS OF METAL-IONS ON THE CONFORMATION OF POLAR HEADGROUP OF SPHINGOMYELIN BILAYER

With the wide application of rare earth in agriculture, medicament, especially the application of Gd-DTPA as nuclear magnetic resonance image reagent in clinical practice([1]), the studies on the toxicology in biological body, as well as the study on the use as informative probes instead of divalent calcium ion in biological and biochemical research have attracted intensive concern([2]). Phospholipids bilayers have served as a model of biomembrane in the last two decades. The effects of metal ions on the conformation of polar headgroup of dipalmitoylphosphatidylcholine (DPPC) bilayers have been reported([3]). Sphingomyelin is major component of several biological tissues such as brain and nerve cells and has identical polar headgroup to DPPC. The interaction of metal ions with sphingomyelin bilayer remains nonrevealed. This note presents the results of the study on this aspect.

NMR-STUDIES ON THE COORDINATION OF RARE-EARTHS WITH GLYCYL-DL-VALINE AND THE CONFORMATION OF THEIR COMPLEX IN AQUEOUS-SOLUTION

In this paper lanthanide-induced shifts have been measured for C-13 and H-1 nuclei of glycyl-DL-valine in the presence of three lanthanide cations (La3+, Ho3+ and Yb3+) in aqueous solution. The stability constants of the coordination compounds of rare earths (Ho, Yb) with glycyl-DL-valine have been calculated. The coordination of rare earths with the ligand has been discussed. The simulation for conformation of lanthanide coordination compounds with glycyl-DL-valine shows that the ligand is coordinated to lanthanide ion through oxygen atoms of carboxyl group and the bond length of Ln-O is 0.226 nm. In the coordination compounds glycyl-DL-valine is in extended state with minimal steric hindrance.

CONFORMATION OF PHENYL RINGS IN THE HELICAL CHAIN POLYMER POLY(TRIPHENYLMETHYL METHACRYLATE)

The conformation of phenyl rings in the side groups of the helical chain polymer poly(tripenyl-methyl methacrylate) (1) in solution was studied by spectroscopic methods. According to the Raman spectrum the phenyl rings of 1 and triphenylmethyl methacrylate in solution have the same depolarization ratio at 1002 cm-1. The electronic spectra (ultraviolet and fluorescence) of 1 are similar to those of model substances, except for the "red shift" of the spectra of about 5 nm. It was concluded that the phenyl rings can rotate around the phenyl-C bond.