Polysomes bypass a 50 nucleotide coding gap less efficiently than monosomes due to attenuation of an unstable 5' mRNA stem loop stimulator and enhanced drop-off

Ribosome profiling analysis of phage T4 infected E. coli yielded protected mRNA fragments within the normal size range derived from ribosomes stalled at the take-off codon. Ribosomes at this position also yielded some 53 nucleotide fragments, 16 longer. These were due to protection of the nucleotides that form the 5' stem loop. Overall design: Ribosome profiling of 'normal' and long protected fragments obtained from T4 infected E.coli or of E.coli with plasmid-borne cassette with the gene 60 sequence