NONUNIFORM SIZE DISTRIBUTION OF NASCENT PEPTIDES - EFFECT OF MESSENGER-RNA STRUCTURE UPON THE RATE OF TRANSLATION

The size distribution of bacteriophage MS2 coat protein nascent chains purified from MS2-infected Escherichia coli has been determined. Accumulations of nascent chains of discrete sizes were observed, providing evidence that the rate of chain elongation during coat protein biosynthesis is not uniform. A correlation of the size of nascent peptides which accumulate during MS2 coat protein biosynthesis and the position on the MS2 coat protein mRNA of the ribosome carrying those lengths of nascent peptides may be made. This correlation leads to the hypothesis that regions of mRNA secondary structure impede the movement of ribosomes during chain elongation and thus serve as the origin of the accumulation of nascent chains of discrete sizes. © 1979.