The amphipathic membrane proteins associated with gangliosides: The Paul-Bunnell antigen is one of the gangliophilic proteins

Two amphipathic protein fractions soluble in organic solvents as well as in water have been isolated from the ganglioside fraction of bovine erythrocyte membranes by successive chromatography in chloroform-methanol mixture on DEAE-Sephadex, silicic acid, and α-hydroxypropylated Sephadex G50 (LH60) columns. These two fractions contained a similar low molecular weight protein but with distinctively different amino acid composition. One of these proteins has been characterized by having a strong Paul-Bunnell antigen activity and had a binding affinity to ganglioside. A similar protein without Paul-Bunnell antigen activity was isolated as the major ganglioside-associated protein.     

Plasma membrane glycosphingolipids (GSLs) of the human lymphoblastoid cell-line BRI 8 and differences between the GSLs of BRI 8 cells and those of peripheral lymphocytes.

A cyclic undecapeptide, Wy-40,770, has been synthesized by a combination of solid phase and conventional peptide synthesis methodology. The compound inhibits the release of growth hormone without significantly affecting glucagon levels in rats. Wy-40,770 shows growth hormone release inhibiting activity for four hours after s.c. injection.     

Mechanism of cell contact-dependent glycolipid synthesis: further studies with glycolipid-glass complex

An initiation factor from rabbit reticulocytes can overcome the block in initiation of protein synthesis occurring in reticulocyte lysates when exogenous hemin is not present, or when double-stranded RNA is added. This factor has been identified with IF-MP, an initiation factor capable of forming ternary complexes with GTP and methionyl-tRNA_F. Initiation factor IF-M3 by itself is unable to overcome the block in initiation, but appears to stimulate this activity of IF-MP. IF-MP binds to single-stranded R17 RNA as well as to double-stranded RNA, while IF-M3 only binds to double-stranded RNA. The protein synthetic activity of IF-MP is sensitive to N-ethylmaleimide, but its ability to bind RNA is resistant.     

Headgroup behaviour of an uncharged complex glycolipid

A globoside spin labelled on the terminal sugar residue has been synthesized, and employed in model membranes to study headgroup behaviour of complex uncharged glycolipids. The labelled headgroup demonstrated a high degree of motional freedom limited to the aqueous region of the interface between lipid bilayer and surrounding medium. This observation was unaltered by the presence of a dense, tightly-bound surface layer of peripheral proteins or polysaccharide—which might be expected to reproduce conditions present at a cell surface. Headgroup dynamics were only very modestly correlated with the physical state (i.e., fluidity) of the membrane itself. In spite of the absence of charged sugar residues in globoside, the aspects of its headgroup behaviour monitored here we found to be similar to those of oligosaccharide chains on gangliosides and several sialic acid-rich glycoproteins.