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Helix 69 is key for uniformity during substrate selection on the ribosome.

ABSTRACT: Structural studies of ribosome complexes with bound tRNAs and release factors show considerable contacts between these factors and helix 69 (H69) of 23 S rRNA. Although biochemical and genetic studies have provided some general insights into the role of H69 in tRNA and RF selection, a detailed understanding of these contributions remains elusive. Here, we present a pre- steady-state kinetic analysis establishing that two distinct regions of H69 make critical contributions to substrate selection. The loop of H69 (A1913) forms contacts necessary for the efficient accommodation of a subset of natural tRNA species, whereas the base of the stem (G1922) is specifically critical for UGA codon recognition by the class 1 release factor RF2. These data define a broad and critical role for this centrally located intersubunit helix (H69) in accurate and efficient substrate recognition by the ribosome.

SUBMITTER: Ortiz-Meoz RF

PROVIDER: S-EPMC3138323 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature

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Helix 69 is key for uniformity during substrate selection on the ribosome.

Ortiz-Meoz Rodrigo F RF Green Rachel R

The Journal of biological chemistry 20110527 29

Structural studies of ribosome complexes with bound tRNAs and release factors show considerable contacts between these factors and helix 69 (H69) of 23 S rRNA. Although biochemical and genetic studies have provided some general insights into the role of H69 in tRNA and RF selection, a detailed understanding of these contributions remains elusive. Here, we present a pre- steady-state kinetic analysis establishing that two distinct regions of H69 make critical contributions to substrate selection. ...[more]

PMID: 21622559

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