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A tandem active site model for the ribosomal helicase
Author(s) -
Amiri Hossein,
Noller Harry F.
Publication year - 2019
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1002/1873-3468.13383
Subject(s) - helicase , ribosome , messenger rna , ribosomal binding site , rna helicase a , ribosomal rna , translational frameshift , biology , genetics , microbiology and biotechnology , chemistry , computational biology , rna , biophysics , gene
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.