Blockade of inflammatory responses by a small-molecule inhibitor of the Rac activator DOCK2

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Highlights? CPYPP binds to DOCK2 DHR-2 domain and inhibits its catalytic activity ? CPYPP inhibits DOCK2-mediated Rac activation in cells ? The structural features of CPYPP required for its inhibitory effect were revealed ? CPYPP inhibits lymphocyte migration and activation in vitro and in vivo     

Can Thiacalixarene Surpass Calixarene?

Heteroatom-bridged calixarenes have been confined intothe unexplored frontier of the vast realm of the calixarene chemistry because of their syntheticdifficulty. Since we found facile one-step synthesis of thiacalix[4]arene, in which four methylenebridges of calix[4]arene are replaced by four sulfides, we have been engaged in the study on thisnew molecular platform regarding the improvements for the synthetic procedures, structuralanalyses, chemical modifications, and functional developments. In this review are describedthe results of our own study to demonstrate the potentials over the limits of the conventionalcalixarenes, putting emphasis on the indispensable role of the bridging sulfur. Highlighted examples are(1) enlargement of the calix skeleton to provide larger cavity, (2) ready oxidizability to sulfoxideand sulfone for providing new members of S bridged calixarenes, and (3) coordination to specificmetal ions controlled by the oxidation state of S. These indicate a hopeful future for thethiacalixarene platform in the forthcoming applications to functional molecular devices.     

Evaluation of the Intracellular Signaling Activities of κ-Opioid Receptor Agonists,Nalfurafine Analogs; Focusing on the Selectivity of G-Protein- and β-Arrestin-Mediated Pathways

Opioid receptors (ORs) are classified into three types (μ, δ, and κ), and opioid analgesics are mainly mediated by μOR activation; however, their use is sometimes restricted by unfavorable effects. The selective κOR agonist nalfurafine was initially developed as an analgesic, but its indication was changed because of the narrow safety margin. The activation of ORs mainly induces two intracellular signaling pathways: a G-protein-mediated pathway and a β-arrestin-mediated pathway. Recently, the expectations for κOR analgesics that selectively activate these pathways have increased; however, the structural properties required for the selectivity of nalfurafine are still unknown. Therefore, we evaluated the partial structures of nalfurafine that are necessary for the selectivity of these two pathways. We assayed the properties of nalfurafine and six nalfurafine analogs (SYKs) using cells stably expressing κORs. The SYKs activated κORs in a concentration-dependent manner with higher EC₅₀ values than nalfurafine. Upon bias factor assessment, only SYK-309 (possessing the 3S-hydroxy group) showed higher selectivity of G-protein-mediated signaling activities than nalfurafine, suggesting the direction of the 3S-hydroxy group may affect the β-arrestin-mediated pathway. In conclusion, nalfurafine analogs having a 3S-hydroxy group, such as SYK-309, could be considered G-protein-biased κOR agonists.     

Amino acid composition analysis of minute amounts of cysteine-containing proteins using 4-(aminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole and 4-fluoro-7-nitro-2,1,3-benzoxadiazole in combination with HPLC

The simultaneous determination of amino acid composition including cysteine of egg albumin, a model protein containing a/s cysteine residue, is reported. All the thiol groups of the cysteine residue(s) of egg albumin were labelled with 4-(aminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole, a fluorogenic reagent for thiol groups. The labeled egg albumin was hydrolyzed in 6N HCl at 110 degrees C for 24 h. The hydrolysate was lyophilized, derivatized with 4-fluoro-7-nitro-2,1,3-benzoxadiazole, a fluorogenic reagent for amines, and subjected to HPLC. 18 derivatized amino acids including double labelled cysteine were separated within 90 min on a Nucleosil ODS column (150 mm X 4.6 mm i.d.; 5 microns), and detected at 530 nm (ex. 470 nm) in a range from 90 fmol (aspartic acid) to 1.3 pmol (cysteine) (S/N = 3). Composition ratios of amino acids of egg albumin were similar to theoretical values except for methionine, which would be destroyed under the present acid hydrolysis condition. Analytical methods for cysteine residues are reviewed, and the availability of fluorogenic reagents having the benzofurazan structure is also discussed.     

Epimerization of diastereomeric alpha-amino nitriles to single stereoisomers in the solid state

[reaction: see text] A diastereomeric mixture of the alpha-amino nitrile prepared by the Strecker reaction of benzaldehyde, (1S,2R)-1-aminoindan-2-ol, and cyanotrimethylsilane thermally epimerizes in the solid state to give a single diastereomer with an (S)-configuration at the alpha position to the nitrile moiety. This shows a sharp contrast to the reaction conducted in DMSO at room temperature, which gives a 1:1 mixture of (S)- and (R)-isomers. Several other alpha-amino nitriles also epimerize in the solid-state toward single diastereomers.