A tandem active site model for the ribosomal helicase

During protein synthesis, the messenger RNA (mRNA) helicase activity of the ribosome ensures that codons are made single stranded before decoding. Here, based on recent structural and functional findings, a quantitative model is presented for a tandem arrangement of two helicase active sites on the...

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Bibliographic Details
Published in:FEBS letters 2019-05, Vol.593 (10), p.1009-1019
Main Authors: Amiri, Hossein, Noller, Harry F.
Format: Article
Language:English
Subjects:
helicase
mechanism
mRNA
ribosome
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Summary:During protein synthesis, the messenger RNA (mRNA) helicase activity of the ribosome ensures that codons are made single stranded before decoding. Here, based on recent structural and functional findings, a quantitative model is presented for a tandem arrangement of two helicase active sites on the ribosome. A distal site encounters mRNA structures first, one elongation cycle earlier than a proximal site. Although unwinding of encountered mRNA structures past the proximal site is required for translocation, two routes exist for translocation past the distal site: sliding, which requires unwinding, and stick‐slip, which does not. The model accounts in detail for a number of findings related to the ribosomal helicase and provides a testable framework to further study mRNA unwinding.
ISSN:0014-5793
1873-3468
DOI:10.1002/1873-3468.13383