PT  - JOURNAL ARTICLE
AU  - Yuhei Chadani
AU  - Nobuyuki Sugata
AU  - Tatsuya Niwa
AU  - Yosuke Ito
AU  - Shintaro Iwasaki
AU  - Hideki Taguchi
TI  - Nascent polypeptide within the exit tunnel ensures continuous translation elongation by stabilizing the translating ribosome
AID  - 10.1101/2021.02.02.429294
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.02.02.429294
4099  - http://biorxiv.org/content/early/2021/02/02/2021.02.02.429294.short
4100  - http://biorxiv.org/content/early/2021/02/02/2021.02.02.429294.full
AB  - Continuous translation elongation, irrespective of amino acid sequences, is a prerequisite for living organisms to produce their proteomes. However, the risk of elongation abortion is concealed within nascent polypeptide products. Negatively charged sequences with occasional intermittent prolines, termed intrinsic ribosome destabilization (IRD) sequences, destabilizes the translating ribosomal complex. Thus, some nascent chain sequences lead to premature translation cessation. Here, we show that the risk of IRD is maximal at the N-terminal regions of proteins encoded by dozens of Escherichia coli genes. In contrast, most potential IRD sequences in the middle of open reading frames remain cryptic. We found two elements in nascent chains that counteract IRD: the nascent polypeptide itself that spans the exit tunnel and its bulky amino acid residues that occupy the tunnel entrance region. Thus, nascent polypeptide products have a built-in ability to ensure elongation continuity by serving as a bridge and thus by protecting the large and small ribosomal subunits from dissociation.Competing Interest StatementThe authors have declared no competing interest.