Mol-ecular structure of tris-[(6-bromo-pyridin-2-yl)meth-yl]amine.

Coordination compounds of polydentate nitro-gen ligands with metals are used extensively in research areas such as catalysis, and as models of complex active sites of enzymes in bioinorganic chemistry. Tris(2-pyridyl-meth-yl)amine (TPA) is a tripodal tetra-dentate ligand that is known to form coordination compounds with metals, including copper, iron and zinc. The related compound, tris-[(6-bromo-pyridin-2-yl)meth-yl]amine (TPABr), CHBrN, which possesses a bromine atom on the 6-position of each of the three pyridyl moieties, is also known but has not been heavily investigated.

A biomimetic gelatin-based platform elicits a pro-differentiation effect on podocytes through mechanotransduction.

Using a gelatin microbial transglutaminase (gelatin-mTG) cell culture platform tuned to exhibit stiffness spanning that of healthy and diseased glomeruli, we demonstrate that kidney podocytes show marked stiffness sensitivity. Podocyte-specific markers that are critical in the formation of the renal filtration barrier are found to be regulated in association with stiffness-mediated cellular behaviors. While podocytes typically de-differentiate in culture and show diminished physiological function in nephropathies characterized by altered tissue stiffness, we show that gelatin-mTG substrates with Young's modulus near that of healthy glomeruli elicit a pro-differentiation and maturation response in podocytes better than substrates either softer or stiffer.

C-H bond functionalization via hydride transfer: Lewis acid catalyzed alkylation reactions by direct intramolecular coupling of sp3 C-H bonds and reactive alkenyl oxocarbenium intermediates.

C-H bond functionalization enables strategically new approaches to the synthesis of complex organic molecules including biologically active compounds, research probes and functional organic materials. To address the shortcomings of transition metal catalyzed processes, we have developed a new approach to direct coupling of sp(3) C-H bonds and alkenes based on Lewis acid-promoted hydride transfer. Activation of alpha,beta-unsaturated aldehydes and ketones with Lewis acid triggers intramolecular hydride transfer, leading to a zwitterionic intermediate, which in turn undergoes ionic cyclization to afford the cyclic alkylation product.

In Vivo Protein-Protein Interaction Assays: Beyond Proteins.

The scope of cell-based assays is being expanded to allow the detection of interactions between proteins and DNA, RNA, or small molecules. The yeast two-hybrid assay, which normally detects protein-protein interactions, can be modified to detect interactions between ligands (the two dark yellow shapes in the diagram) and receptors (DHFR or GR). A small bridging molecule (made up of the ligands joined together) is used to join two fusion proteins (DHFR-DBD and AD-GR), thereby activating the reporter gene.