Nascent polypeptide within the exit tunnel ensures continuous translation elongation by stabilizing the translating ribosome

摘要: Continuous translation elongation, irrespective of amino acid sequences, is a prerequisite for living organisms to produce their proteomes. However, the risk elongation abortion concealed within nascent polypeptide products. Negatively charged sequences with occasional intermittent prolines, termed intrinsic ribosome destabilization (IRD) destabilizes translating ribosomal complex. Thus, some chain lead premature cessation. Here, we show that IRD maximal at N-terminal regions proteins encoded by dozens Escherichia coli genes. In contrast, most potential in middle open reading frames remain cryptic. We found two elements chains counteract IRD: itself spans exit tunnel and its bulky residues occupy entrance region. products have built-in ability ensure continuity serving as bridge thus protecting large small subunits from dissociation.