To address this issue, we overexpressed the Saccharomyces cerevisiae soluble alpha Glu, Cwht1p, in the host Pichia pastoris. It was purified in a simple two-step protocol, with a final yield of 4.2 mg Cwht1p per liter of growth culture. To test catalytic activity, we developed a modified synthesis of a tetrasaccharide substrate, Glc(3)ManOMe. Cwht1p with Glc(3)ManOMe shows a K-m of 1.26 mM. Cwht1p crystals were grown and subjected to X-ray irradiation, giving a complete diffraction dataset to 2.04 angstrom resolution. Work is ongoing to obtain phases so that we may further understand this Selleckchem AZD5153 fundamental member of the N-glycosylation pathway through

the discovery of its molecular structure. (C) 2011 Elsevier Inc. All rights reserved.”
“In this paper we propose a mechanism for the formation of paths of minimal length between two points (trails) by a collection of individuals undergoing reinforced click here random walks. This is the case, for instance, of ant colonies in search for food and the development of ant trails connecting nest and food source. Our mechanism involves two main ingredients:

(1) the reinforcement due to the gradients in the concentration of some substance (pheromones in the case of ants) and (2) the persistence understood as the tendency to preferably follow straight directions in the absence of any external effect. Our study involves the formulation and analysis of suitable Markov chains for the motion in simple labyrinths, that will be understood as graphs, and numerical computations in more complex graphs reproducing experiments performed in the past with ants. (c) 2012 Elsevier Ltd. All rights reserved.”
“Nicotinic acetylcholine receptors (nAChRs) selleck form ligand-gated ion channels

that mediate fast signal transmission at synapses. These receptors are members of a large family of pentameric ion channels that are of active medical interest. An expression system utilizing a chimerical construct of the N-terminal extracellular ligand binding domain of alpha7 type nAChR and the C-terminal transmembrane portion of 5HT3 type receptor resulted high level of expressions. Two ligand affinity chromatography purification methods for this receptor have been developed. One method relies on the covalent immobilization of a high affinity small molecule alpha7 nAChR agonist, (R)-5-(4-aminophenyl)-N-(quinuclidin-3-yl) furan-2-carboxamide, and the other uses mono biotinylated alpha-bungarotoxin, an antagonist, that forms a quasi-irreversible complex with alpha7 nAChR. Detergent solubilized alpha7/5HT(3) chimeric receptors were selectively retained on the affinity resins and could be eluted with free ligand or biotin. The proteins purified by both methods were characterized by gel electrophoresis, mass spectra, amino acid composition analysis, and N-terminal sequence determination. These analyses confirmed the isolation of a mature alpha7/5HT(3) receptor with the signal peptide removed.