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Rigid Backbone (rigid + backbone)
Selected AbstractsEnhanced docking with the mining minima optimizer: Acceleration and side-chain flexibilityJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 16 2002Visvaldas Kairys Abstract The ligand,protein docking algorithm based on the Mining Minima method has been substantially enhanced. First, the basic algorithm is accelerated by: (1) adaptively determining the extent of each energy well to help avoid previously discovered energy minima; (2) biasing the search away from ligand positions at the surface of the receptor to prevent the ligand from staying at the surface when large sampling regions are used; (3) quickly testing multiple different ligand positions and orientations for each ligand conformation; and (4) tuning the source code to increase computational efficiency. These changes markedly shorten the time needed to discover an accurate result, especially when large sampling regions are used. The algorithm now also allows user-selected receptor sidechains to be treated as mobile during the docking procedure. The energies associated with the mobile side chains are computed as if they belonged to the ligand, except that atoms at the boundary between side chains and the rigid backbone are treated specially. This new capability is tested for several well-known ligand/protein systems, and preliminary application to an enzyme whose substrate is unknown,the recently solved hypothetical protein YecO (HI0319) from Haemophilus influenzae,indicates that side-chains relaxations allow candidate substrates of various sizes to be accommodated. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 1656,1670, 2002 [source] One- and Two-Component Bottle-Brush Polymers: Simulations Compared to Theoretical PredictionsMACROMOLECULAR THEORY AND SIMULATIONS, Issue 7 2007Hsiao-Ping Hsu Abstract Scaling predictions for bottle-brush polymers with a rigid backbone and flexible side chains under good solvent conditions are discussed and their validity is assessed by a comparison with Monte Carlo simulations of a simple lattice model. It is shown that typically only a rather weak stretching of the side chains is realized, and then the scaling predictions are not applicable. Also two-component bottle brush polymers are considered, where two types (A,B) of side chains are grafted, assuming that monomers of different kind repel each other. In this case, variable solvent quality is allowed. Theories predict "Janus cylinder"-type phase separation along the backbone in this case. The Monte Carlo simulations, using the pruned-enriched Rosenbluth method (PERM) give evidence that the phase separation between an A-rich part of the cylindrical molecule and a B-rich part can only occur locally. The correlation length of this microphase separation can be controlled by the solvent quality. This lack of a phase transition is interpreted by an analogy with models for ferromagnets in one space dimension. [source] High-Performance Membranes from Polyimides with Intrinsic Microporosity,ADVANCED MATERIALS, Issue 14 2008Bader S. Ghanem Membranes with high permeability to gases are formed from polyimides with rigid backbones that incorporate a spiro-centre (see figure). A route to this new range of high-free-volume polyimides is demonstrated, and exceptional performance is obtained for a polymer containing a dimethyl binaphthyl unit. [source] Liquid-crystalline and light-emitting polyacetylenesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 17 2003Jacky W. Y. Lam Abstract Rigid polymer backbones have often been considered to be detrimental to the packing of mesogenic pendants, and polyacetylenes have generally been regarded as unpromising materials for light-emitting applications. Our group, however, has succeeded in creating a series of liquid-crystalline polyacetylenes with rigid backbones and a variety of light-emitting polyacetylenes with luminescent chromophores. Here we demonstrate that the rigid polyacetylene skeleton can play a constructive role in guiding the alignments of mesogenic pendants and prove that polyacetylenes can be highly emissive with photoluminescence quantum yields of up to 98% and electroluminescence performances comparable or superior to those of the best blue-light-emitting polymers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2607,2629, 2003 [source] | ||||||||||