title: Protein synthesis and competitive ESR binding studies with E. coli ribosomes and spin-labeled polynucleotides.
abstract: Enzymatically prepared spin labeled copolymers of (U)n were tested for their ability to direct polyphenylalanine synthesis in vitro using E. coli B enzymes and ribosomes. Spin labeling of the C5 position using (RUGT,U)n (1:100) or (RUTT,U)n (1:100) did not alter the amount of polyphenylalanine formed in comparison to (U)n. In contrast, the C4 spin labeled copolymer (ls4U,U)n (1:100) reduced phenylalanine incorporation by 70-75% of the (U)n control levels. ESR monitoring of competitive ribosome binding to equimolar mixtures of polynucleotides was demonstrated with the macromolecular probe (DUTT,dT)n (1:100), the DNA analogue of (RUTT,U)n. The ESR competition approach showed that the affinity of the ribosomes was essentially the same for (dT)n, (A,U,G)n, and (A,U,G)n + tRNArmet.
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D004578:Electron Spin Resonance Spectroscopy; D004926:Escherichia coli / Q000378:metabolism*; D010455:Peptides / Q000235:genetics; D011072:Poly U / Q000235:genetics; D011131:Polyribonucleotides / Q000235:genetics*; D014176:Protein Biosynthesis; D012270:Ribosomes / Q000378:metabolism*; D013113:Spin Labels
chemical_list: D001426:Bacterial Proteins; D010455:Peptides; D011131:Polyribonucleotides; D013113:Spin Labels; D011072:Poly U; C012001:polyphenylalanine