The synthesis of the unusual alkaloid concavine, isolated from Clitocybe concava (Basidiomycetae), has been accomplished. The synthetic route features regio- and stereoselective manipulation of polycyclic imide intermediates via enolate substitution and Grignard addition, along with a key bridge-forming step involving a new method for sulfenylative radical cyclisation. The NMR data for syntheti...

Correct determination of absolute values and polarities of liquid junction potentials (LJPs) is essential in patch clamp experiments for the estimation of ionic selectivities and activation voltages of ion channels. A simple approach for the correction of membrane voltages for LJPs has been developed. The method covers all combinations of LJPs between the solutions of bath, patch pipette and re...

Monosubstituted [4-carboxy-2,6-dinitrophenyl-lysine]cytochromes c were investigated by n.m.r. and e.p.r. Modification of Lys-13 or Lys-72 in ferricytochrome c by 4-chloro-3,5-dinitrobenzoate yields either of two different conformers that are rapidly exchanging in the native form. The equilibrium involves small local changes in the conformation of Met-80 (the sixth ligand) and Phe-82, as a resul...

The title compound, C(17)H(25)ClN(3)O(3) (+)·Cl(-)·H(2)O, is a monohydrated hydro-chloride salt of a new derivative of mosapride, which is a pharmaceutical compound possessing gastrointestinal pro-kinetic activity. The chloride anion accepts hydrogen bonds from the NH group of the pyrrolooxazine fused-ring system and from the amine group, and the water mol-ecules form hydrogen bonds that bridge...

In the title salt, [C(6)H(5)N(CH(3))(3)][Sn(2)Br(5)(C(7)H(6)Br)(4)], the Sn(IV) atoms of the dinuclear anion are bridged by a Br atom; the Sn-Br(bridge) bond lengths are 2.9818 (5) and 3.0470 (5) Å. Both Sn atoms show a distorted cis-trigonal-bipyramidal coordination geometry that is distorted towards a square pyramid. In the crystal, weak C-H⋯π inter-actions occur between anions and cations.

The synthesis of the unusual alkaloid concavine, isolated from Clitocybe concava (Basidiomycetae), has been accomplished. The synthetic route features regioand stereoselective manipulation of polycyclic imide intermediates via enolate substitution and Grignard addition, along with a key bridge-forming step involving a new method for sulfenylative radical cyclisation. The NMR data for synthetic ...

The Generalized Born (GB) continuum solvent model is arguably the most widely used implicit solvent model in protein folding and protein structure prediction simulations; however, it still remains an open question on how well the model behaves in these large-scale simulations. The current study uses the beta-hairpin from C-terminus of protein G as an example to explore the folding free energy l...

Chloride binding in photosystem II (PSII) is essential for photosynthetic water oxidation. However, the functional roles of chloride and possible binding sites, during oxygen evolution, remain controversial. This paper examines the functions of chloride based on its binding site revealed in the X-ray crystal structure of PSII at 1.9 Å resolution. We find that chloride depletion induces formatio...

The central domain of smooth muscle caldesmon contains a highly charged region consisting of ten 13-residue repeats. Experimental evidence obtained from the intact protein and fragments thereof suggests that this entire region forms a single stretch of stable alpha-helix. We have carried out molecular dynamics simulations on peptides consisting of one, two and three repeats to examine the mecha...

When depth of flow past a river bridge exceeds opening under the bridge, the flow under the bridge becomes pressurized. The water is directed downward and under the bridge deck, causing increase in velocity and shear stress on the bed thereby increasing bed scour. This is termed as Pressure Flow Scour. The present study investigates the phenomenon of pressure flow scour resulting from a submerg...