Using dynamic correlations obtained from explicit solvent molecular dynamic simulations we illustrate the key roles played by allostery in both mechanisms. Pre-existence of conformational states explains the experimental observations that sumoylation can occur without E3, even though at

a reduced rate. Furthermore, we propose a mechanism for enhancement of sumoylation by E3. Analysis of the conformational ensembles of the complex of E2 conjugated ATM/ATR tumor to SUMO illustrates that the E2 enzyme is already largely pre-organized for target binding and catalysis; E3 binding shifts the equilibrium and enhances these pre-existing populations. We further observe that E3 binding regulates allosterically the key residues in E2, Ubc9 Asp100/Lys101 E2, for the target recognition.”
“Crystalline dicarboxylated poly(L-lactic acid)s (dcPLLAs) with number-average molecular weights (M(n)’s) of 10(3) to 10(4) g/mol were synthesized via the melt polycondensation of L-lactic acid (LLA) in the presence of succinic anhydride (SAD), with tin(II) NSC23766 in vitro chloride and toluene-4-sulfonic acid as binary catalysts. They were characterized by end-group titration, (1)H-NMR, differential scanning calorimetry, and wide-angle X-ray diffraction. The terminal COOH percentage reached over 98%, and the molecular weight could be controlled by the molar ratio of LLA to SAD. The

thermal behaviors depended on the molecular weight. The poly(L-lactic acid) s (PLLAs) crystallized slowly for M(n) <= 2000 but quickly for M(n) >= 4000. The crystallinity increased from 27 to 40% when M(n) grew from 4000 to 10,000. With comparison to ordinary PLLA, the dcPLLA had the same crystallization structure but a slightly lower crystallizability. The glass-transition temperature was clearly higher than that of amorphous dcPLLAs. With a controllable molecular weight, high COOH percentage, and crystallinity, the dcPLLA with M(n) >= 4000 appeared to be a suitable prepolymer for the preparation of high-molecular-weight crystalline PLLA via Ferrostatin-1 chain extension. (C) 2011Wiley Periodicals,

Inc. J Appl Polym Sci 121: 3246-3251, 2011″
“We have studied electric-field-induced symmetry lowering in the tetragonal (001)-oriented heteroepitaxial (Ba0.8Sr0.2)TiO3 thin film deposited on (001) MgO substrate. Polarized micro-Raman spectra were recorded from the film area in between two planar electrodes deposited on the film surface. Presence of c domains with polarization normal to the substrate was confirmed from polarized Raman study under zero field, while splitting and hardening of the E(TO) soft mode and polarization changes in the Raman spectra suggest monoclinic symmetry under external electric field. (C) 2011 American Institute of Physics. [doi:10.1063/1.3573516]“
“Various characteristics of complex gene regulatory networks (GRNs) have been discovered during the last decade, e. g.