Amino acid-dependent stability of the acyl linkage in aminoacyl-tRNA.

Aminoacyl-tRNAs are the biologically active substrates for peptide bond formation in protein synthesis. The stability of the acyl linkage in each aminoacyl-tRNA, formed through an ester bond that connects the amino acid carboxyl group with the tRNA terminal 3'-OH group, is thus important. While the ester linkage is the same for all aminoacyl-tRNAs, the stability of each is not well characterized, thus limiting insight into the fundamental process of peptide bond formation. Here, we show, by analysis of the half-lives of 12 of the 22 natural aminoacyl-tRNAs used in peptide bond formation, that the stability of the acyl linkage is effectively determined only by the chemical nature of the amino acid side chain. Even the chirality of the side chain exhibits little influence. Proline confers the lowest stability to the linkage, while isoleucine and valine confer the highest, whereas the nucleotide sequence in the tRNA provides negligible contribution to the stability. We find that, among the variables tested, the protein translation factor EF-Tu is the only one that can protect a weak acyl linkage from hydrolysis. These results suggest that each amino acid plays an active role in determining its own stability in the acyl linkage to tRNA, but that EF-Tu overrides this individuality and protects the acyl linkage stability for protein synthesis on the ribosome.

Correction: Mathur et al. Effectiveness of a Theory-Informed Documentary to Reduce Consumption of Meat and Animal Products: Three Randomized Controlled Experiments. Nutrients 2021, 13, 4555.

The authors wish to make the following correction to this paper [...].

Effectiveness of a Theory-Informed Documentary to Reduce Consumption of Meat and Animal Products: Three Randomized Controlled Experiments.

Several societal issues could be mitigated by reducing global consumption of meat and animal products (MAP). In three randomized, controlled experiments (n=217 to 574), we evaluated the effects of a documentary that presents health, environmental, and animal welfare motivations for reducing MAP consumption. Study 1 assessed the documentary's effectiveness at reducing reported MAP consumption after 12 days. This study used methodological innovations to minimize social desirability bias, a widespread limitation of past research. Study 2 investigated discrepancies between the results of Study 1 and those of previous studies by further examining the role of social desirability bias. Study 3 assessed the documentary's effectiveness in a new population anticipated to be more responsive and upon enhancing the intervention content. We found that the documentary did not decrease reported MAP consumption when potential social desirability bias was minimized (Studies 1 and 3). The documentary also did not affect consumption among participants whose demographics suggested they might be more receptive (Study 3). However, the documentary did substantially increase intentions to reduce consumption, consistent with past studies (Studies 2 and 3). Overall, we conclude that some past studies of similar interventions may have overestimated effects due to methodological biases. Novel intervention strategies to reduce MAP consumption may be needed.