The conformation of the Escherichia coli initiator tRNA has been investigated using enzymatic and chemical probes. This study was conducted on the naked tRNA and on the tRNA involved in the various steps leading to the formation of the 30 S.IF-2.GTP.fMet-tRNA.AUG complex. A three-dimensional model of the initiator tRNA is presented, which displays several differences with yeast tRNAPhe: (i) the...

Polymers with a low molecular weight derived from soybean oil have been prepared in a supercritical carbon dioxide medium by cationic polymerization. Boron trifluoride diethyl etherate was used as an initiator. Influences of polymerization temperature, amount of initiator, and carbon dioxide pressure on the molecular weight were investigated. It is shown that the higher polymerization temperatu...

Mixed yeast elongator-tRNAs (bulk tRNA lacking fRNAm,fMet), pure isoaccepting species of elongator-tRNAs (tRNAmMet and tRNAPhe), and purified initiator-tRNA (tRNAfMet) were each oxidized with periodate and the 3' terminus was coupled to Sepharose 4B through an adipic acid dihydrazide spacer. The rat liver ribosomal proteins that associated with the tRNAs were isolated by affinity chromatography...

Polymer nanocomposites of core–shell structure were prepared by grafting poly(methyl methacrylate) (PMMA) from TiO2 nanoparticle via the surface-initiated polymerization (SIP) strategy. A bifunctional polymerization initiator inspired by L-3,4-dihydroxyphenylalanine (DOPA), a key constituent of mussel adhesive proteins (MAPs), was designed and synthesized for use in SIP from oxide surfaces. The...

Hydrosilylation of acetylene with a chiral silane, R-(+)-methyl-1-naphthylphenylsilane [R-(+)-MeNpPhSi*H], in the presence of H2PtCl6·xH2O proceeds with retention of the configuration of the stereogenic silicon center and produces a chiral vinylsilane or silylethylene [S-(+)-MeNpPhSi*Vi] of high optical purity under mild conditions (50°C) in high chemical yield (85%). Anionic polymerizations of...

Poly-N-isopropylacrylamide (polyNIPA) is an extensively studied polymer in the field of controlled drug delivery. PolyNIPA contains carbonyl and amide groups along a hydrophobic chain. In an aqueous environment, crosslinked polyNIPA forms a gel characterized by a reversible volume phase transition temperature (VPTT), in response to changes in the external environment excited by the temperature ...

Formylation of initiator methionyl-tRNA is essential for normal growth of eubacteria. However, under special conditions, it has been possible to initiate protein synthesis with unformylated initiator tRNA even in eubacteria. Earlier studies suggested that the lack of ribothymidine (rT) modification in initiator tRNA may facilitate initiation in the absence of formylation. In this report we show...

The rolling circle plasmids of Staphylococcus aureus regulate their replication by controlling initiator (Rep) protein synthesis. It was demonstrated recently that the pT181 initiator protein RepC is inactivated during pT181 replication by the addition of an oligodeoxynucleotide, giving rise to a new form, RepC* (A. Rasooly and R. P. Novick, Science, 262:1048-1050). We establish here that this ...

Synthesized graft copolymers of chloroprene rubber with acrylic acid. A mixture benzene and dimethylformamide was used as a solvent, potassium persulfate polymerization initiator. Based on the dependence copolymerization rate concentrations components temperature, order reaction in terms concentration acid (2.0), (1.2) activation energy process (24.4 kJ/mole) were determined. The degree graftin...