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Coupling of mRNA Structure Rearrangement to Ribosome Movement during Bypassing of Non-coding Regions.


ABSTRACT: Nearly half of the ribosomes translating a particular bacteriophage T4 mRNA bypass a region of 50 nt, resuming translation 3' of this gap. How this large-scale, specific hop occurs and what determines whether a ribosome bypasses remain unclear. We apply single-molecule fluorescence with zero-mode waveguides to track individual Escherichia coli ribosomes during translation of T4's gene 60 mRNA. Ribosomes that bypass are characterized by a 10- to 20-fold longer pause in a non-canonical rotated state at the take-off codon. During the pause, mRNA secondary structure rearrangements are coupled to ribosome forward movement, facilitated by nascent peptide interactions that disengage the ribosome anticodon-codon interactions for slippage. Close to the landing site, the ribosome then scans mRNA in search of optimal base-pairing interactions. Our results provide a mechanistic and conformational framework for bypassing, highlighting a non-canonical ribosomal state to allow for mRNA structure refolding to drive large-scale ribosome movements.

SUBMITTER: Chen J 

PROVIDER: S-EPMC4813330 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature

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Coupling of mRNA Structure Rearrangement to Ribosome Movement during Bypassing of Non-coding Regions.

Chen Jin J   Coakley Arthur A   O'Connor Michelle M   Petrov Alexey A   O'Leary Seán E SE   Atkins John F JF   Puglisi Joseph D JD  

Cell 20151101 5


Nearly half of the ribosomes translating a particular bacteriophage T4 mRNA bypass a region of 50 nt, resuming translation 3' of this gap. How this large-scale, specific hop occurs and what determines whether a ribosome bypasses remain unclear. We apply single-molecule fluorescence with zero-mode waveguides to track individual Escherichia coli ribosomes during translation of T4's gene 60 mRNA. Ribosomes that bypass are characterized by a 10- to 20-fold longer pause in a non-canonical rotated sta  ...[more]