Maurice H. Vaughan

Polyadenylic Acid Sequences in the Virion RNA of Poliovirus and Eastern Equine Encephalitis Virus

Poliovirus virion RNA contains a single covalently bound sequence of polyadenylic acid which is approximately 49 nucleotides long. A single, slightly longer polyadenylic acid sequence is contained in Eastern Equine Encephalitis virus RNA. Since these viruses are otherwise dissimilar these sequences may play a common role in viral replication, possibly in translation of the viral RNA.

Binding of trichodermin to mammalian ribosomes and its inhibition by other 12,13-epoxytrichothecenes

SummaryTrichodermin binds to ribosomes from rabbit reticulocyte polysomes with an apparent Ka of 9.2 × 105 and with a maximum binding ratio of 0.44 molecules per ribosome. Trichodermin also binds firmly to HeLa cell polysomes under conditions where it is inhibiting protein synthesis. Purified HeLa 60S ribosomal subunits showed only a slight ability to bind trichodermin, and no binding was found with 40S subunits. Seventeen 12,13-epoxytrichothecenes were tested for their ability to interfere with [3H] trichodermin binding to reticulocyte ribosomes. All compounds known to inhibit ribosomal functions required for elongation-termination or initiation processes exhibited significant positive interference with the binding of trichodermin.

Gel centrifugation chromatography for macromolecular separations

Abstract A method for chromatographic separation of macromolecules by the use of centrifugation through gel filtration materials is described. The liquid excluded from the gel material is removed by centrifugation; thus, this method offers rapid separation and minimal dilution of samples. Because of the rapid separations obtained, this method is particularly suitable for study of enzyme reactions, ligand binding and formation of intermolecular complexes in general. Within the limitations of the short columns which were employed in the centrifuge, the resolution of macromolecules is equivalent on columns eluted conventionally and columns eluted with the assistance of centrifugation.

Influence of valine deprivation and its reversal on fatty acid metabolism in HeLa cells.

The effects that amino acid starvation and re-supplementation have on fatty acid metabolism in HeLa cells have been studied using radio gas chromatographic techniques. Deprivation of valine for 13.5 h caused fatty acid de novo biosynthesis, elongation and desaturation to cease. This effect was reversed within 5 h by adding valine back to the culture. During deprivation accumulation of triacylglycerol occurred. The return of valine to the culture caused compositional changes in the triacylglycerols and phosphatidylcholines.

Purification and phosphorylation of human initiation factor eIF-2

Summary We have purified human initiation factor 2 (eIF-2) from HeLa cells to near homogeneity. The three major peptide bands seen on a one-dimensional gel of human eIF-2 after rRNA cellulose chromatography are coincident with the three major peptides of rabbit eIF-2. We have shown that the α subunit of human eIF-2 can be phosphorylated by the rabbit hemin controlled repressor. Human and rabbit eIF-2α migrate identically on two-dimensional acrylamide gels.