Tumor necrosis factor receptor superfamily members convey signals that promote diverse cellular responses. Receptor trimerization by extracellular ligands initiates signaling by recruiting members of the tumor necrosis factor receptor-associated factor (TRAF) family of adapter proteins to the receptor cytoplasmic domains. We report the 2.4-A crystal structure of a 22-kDa, receptor-binding fragm...

The influenza virus hemagglutinin (HA) is a well-characterized integral membrane glycoprotein composed of three identical subunits. We have analyzed the formation of mixed trimers in cells expressing two different HA gene products. The results show efficient and essentially random assembly of functional hybrid trimers provided that the HAs are from the same HA subtype. Trimerization is thus a p...

In recent years, structural studies have identified a number of bacterial, viral, and eukaryotic adhesive proteins that have a trimeric architecture. The prototype examples in bacteria are the Haemophilus influenzae Hia adhesin and the Yersinia enterocolitica YadA adhesin. Both Hia and YadA are members of the trimeric-autotransporter subfamily and are characterized by an internal passenger doma...

Cr(III) complexes of tridentate SNS ligands have been prepared and evaluated as catalysts for ethylene trimerization, with several giving very high activity and excellent selectivity toward 1-hexene when activated with methylaluminoxane. The new complexes illustrate the potential of sulfur-based ligands on early transition metals for catalysis.

gem-Selective cross-dimerization and trimerization of silylacetylenes with alkynes via C-H activation using a rhodium(I)-pyridine-Nheterocyclic carbene catalyst have been developed. This protocol is applicable to variety of aliphatic or aromatic terminal alkynes, internal alkynes and gem-1,3-disubsituted enynes to afford the corresponding enynes and dienynes with high regioand stereoselectiviti...

An Al(porphyrin) functionalized with a large axial ligand was incorporated into a porous organic polymer (POP) using a cobalt-catalyzed acetylene trimerization strategy. Removal of the axial ligand afforded a microporous POP that is catalytically active in the methanolysis of a nerve agent simulant. Supercritical CO2 processing of the POP dramatically increased the pore size and volume, allowin...

The human immunodeficiency virus type 1 (HIV-1) exterior envelope glycoprotein, gp120, mediates binding to the viral receptors and, along with the transmembrane glycoprotein gp41, is a major target for neutralizing antibodies. We asked whether replacing the gp41 fusion/trimerization domain with a stable trimerization motif might lead to a more stable gp120 trimer that would be amenable to struc...

The chiral self-assembly of trispentahelicene propellers on a gold surface has been investigated in ultrahigh vacuum by means scanning tunneling microscopy and time-of-flight secondary ion mass spectrometry. aggregate into mirror domains with an enantiomeric ratio 2 : 1. Thermally induced cyclodehydrogenation leads to planarization nanographenes, which self-assemble closed-packed layers two dif...

A series of highly porous polymers with similar BET surface areas of higher than 1000 m(2) g(-1) but tunable pore ranging from 0.7 nm to 0.9 nm were synthesized through facile ethynyl trimerization reaction to demonstrate the surface property-hydrogen adsorption relationship.