Nucleic Acids Research, 1981, Vol. 9, No. 20 5483-5492
© 1981
MOLECULAR BIOLOGY |
Protein synthesis and competitive ESR binding studies with E. coli ribosomes and spin-labeled polynucleotides
Department of Chemistry, University of Cincinnati Cincinnati, OH 45221, USA +Department of Biology, University of Cincinnati Cincinnati, OH 45221, USA
*To whom correspondence should be addressed
Received June 29, 1981. 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 (ls4 U,U)n (1:100) reduced phenylalanine incorporation by 70-75% of the (U)n control levels. DESR 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). 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 + tRNAfmet.