The B oligomer of pertussis toxin was purified from culture supernatants of Bordetella pertussis strains which do not secrete the S1 subunit. The purified B oligomer is devoid of toxicity for CHO cells and other in vivo properties of the toxin, such as leukocytosis and histamine sensitization, but it retains the abilities to agglutinate erythrocytes and to induce the proliferation of T lymphocy...

Novel oligomer metal complexes (2a-f) of the ligand 2,5-bis((4-bromophenyl)carbamoyl) terephthalic acid (1) were prepared using transition metal salts and characterized by various spectroscopic techniques. The geometry of oligomer metal complexes was carried out by electronic spectral analysis and magnetic measurement studies. Polymeric properties have also been carried out. Ligand was synthesi...

The Gay-Berne (GB) potential has been a popular semiempirical model for describing the short-range intermolecular forces for a wide variety of aspherical molecules, including liquid crystals and anisotropic colloids, with generally small molecular dimensions and low aspect ratios (<5). This study evaluates the parametrization of the GB potential for a high-aspect-ratio (=10) oligomer belonging ...

The self-assembly of polypeptides into amyloid structures is associated with a range of increasingly prevalent neurodegenerative diseases as well as with a select set of functional processes in biology. The phenomenon of self-assembly results in species with dramatically different sizes, from small oligomers to large fibrils; however, the kinetic relationship between these species is challengin...

Photofrin (porfimer sodium) is a porphyrin derivative used in the treatment of a variety of cancers by photodynamic therapy. This oligomer complex and a variety of porphyrin monomers, dimers and trimers were analyzed with five different mass spectral ionization techniques: fast atom bombardment, UV and IR matrix-assisted laser desorption/ionization, electrospray ionization, and laser desorption...

We report molecular dynamics simulations of the equilibrium folding/unfolding thermodynamics of the RNA tetraloop in explicit solvent. A replica exchange molecular dynamics study of the r(CGUUGCCG) oligomer that forms a hairpin is performed for 226 ns per replica, using 52 replicas. We are able to show the unbiased folding of all replicas starting from extended conformations. The equilibrium pr...

The deoxyoligonucleotide 5' AATCGGGCATGGATT (15-mer) was synthesized containing 12 phosphoramidate linkages derived from 2 primary and 2 secondary amines. The oligonucleotides were purified by reverse phase HPLC and characterized by PAGE. The thermal stability of the duplexes derived from these compounds, when hybridized to the complementary diester linked oligomer, were determined and compared...

A cluster anion of vinyl compounds in the gaseous phase has served as one of the simplest microscopic models of the initial stages of anionic polymerization. Herein, we describe our investigations into the initial stage mechanisms of anionic polymerization of acrylonitrile (AN; CH2═CHCN) trimer anions. While the cyclic oligomer is found in mass and photoelectron spectroscopic studies of (AN)3(-...

Living systems produce copies of information-carrying molecules such as DNA by assembling monomer units into finite-length oligomer (short polymer) copies. We explore the role initiation and termination copy process in thermodynamics copying. By splitting free-energy change formation informational chemical terms, we show that accuracy plays no direct overall thermodynamics. Instead, it is therm...

Soluble beta-amyloid (Aβ) oligomer is believed to be the most important toxic species in the brain of Alzheimer's disease (AD) patients. Thus, it is critical to develop a simple method for the selective detection of Aβ oligomer with low cost and high sensitivity. In this paper, we report an electrochemical method for the detection of Aβ oligomer with a peptide as the bioreceptor and silver nano...