Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/109264

Translation efficiency is maintained at elevated temperature in E. coli

Morgan, G. J.·Burkhardt, D. H.·Kelly, J. W.·Powers, E. T.
View original source ↗Export metadata ↓

Abstract

Cellular protein levels are dictated by the balance between gene transcription, mRNA translation and protein degradation, among other factors. Cells must manage their proteomes during stress; one way in which they may do so, in principle, is by differential translation. We used ribosome profiling to directly monitor translation in E. coli at 30 {degrees}C and investigate how this changes after 10-20 minutes of heat shock at 42 {degrees}C. Translation is controlled by the interplay of several RNA hybridization processes, which are expected to be temperature sensitive. However, translation efficiencies are robustly maintained after thermal heat shock and after mimicking the heat shock response transcriptional program at 30 {degrees}C. Several gene-specific parameters correlated with translation efficiency, including predicted mRNA structure and whether a gene is cotranslationally translocated into the inner membrane. Genome-wide predictions of the temperature dependence of mRNA structure suggest that relatively few genes show a melting transition between 30 {degrees}C and 42 {degrees}C, consistent with our observations. A linear model with five parameters can predict 33% of the variation in translation efficiency between genes, which may be useful in interpreting transcriptome data.

Source connections

Explore related subjects

biochemistryPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Morgan, G. J., Burkhardt, D. H., Kelly, J. W., Powers, E. T.. 2017-02-16. Translation efficiency is maintained at elevated temperature in E. coli. https://doi.org/10.1101/109264

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Direct Bioconjugations of Diverse Payloads using an Extraordinarily Donor-Promiscuous Flavin Transferase

Site-specific protein conjugation is a widely used tool in chemical biology research and is the foundation of many biotechnological and biomedical applications. A key enabling technology are repurposed post-translational protein modifying enzymes, where variants with broad donor and acceptor substrate promiscuity were developed into general-purpose bioconjugation platforms. However, direct enzymatic attachment of bulky or structurally diverse payloads is often limited by low reaction efficiencies and difficulties in preparing suitable donors. Consequently, conjugation typically relies on two-step strategies in which an enzyme first installs a bioorthogonal handle on the target protein, followed by chemical attachment of the payload. These enzyme-first, chemistry-second approaches limit chemistry to bioorthogonal reactions that leave a molecular footprint. Here, we introduce direct ADDing, an enzymatic bioconjugation platform based on our discovery of the exceptional donor promiscuity of the flavin transferase ApbE. We show that ApbE accepts a remarkably broad range of donor substrates provided they carry an adenosine diphosphate (ADP) anchor. The prevalence of ADP-containing compounds in nature provides access to diverse building blocks and an extensive biochemical toolbox for donor generation. Exploiting these resources, we demonstrate multiple strategies for preparing compatible donors and achieve direct, site-specific enzymatic conjugation of diverse small molecules, peptides, proteins, and synthetic polymers.

biochemistry↗
bioRxiv2026

A respiratory microdomain links ubiquinone biosynthesis to succinate dehydrogenase in an apicomplexan mitochondrion lacking Complex I

Mitochondrial complex I (CI) is a major entry point for NADH-derived electrons and an important site of redox regulation in most eukaryotes. However, apicomplexan parasites, including Toxoplasma gondii, lack CI, raising a fundamental question of how mitochondrial respiration is organized in these parasites. Here, we identify a parasite-specific mitochondrial microdomain that physically and functionally couples ubiquinone (UQ) biosynthesis to succinate dehydrogenase (SDH). Using proximity labeling, membrane-based yeast two-hybrid analyses, reciprocal co-immunoprecipitations, and blue native PAGE, we show that UQ biosynthesis proteins associate with parasite-specific SDH subunits and co-migrate as a high-molecular-weight assembly. Knockdown of TgCoq4, a component of the UQ biosynthesis pathway, reduced SDH activity, and adding exogenous UQ to the assay did not restore it, indicating that UQ availability is not sufficient for efficient succinate oxidation. FCCP stimulates malate- and TMPD/ascorbate-supported respiration to maximal capacity but fails to do so with succinate as the substrate. This result, combined with reactive oxygen species (ROS) data, suggests that succinate causes over-reduction of the UQ pool, limiting further electron flow. We also find that CIII associates with the UQ synthesis machinery, suggesting a larger protein assembly. Together, these findings reveal that UQ biosynthesis and electron transport are physically and functionally integrated in T. gondii, defining a previously unrecognized organization of mitochondrial respiration in an organism lacking CI.

biochemistry↗
bioRxiv2026

Structural Basis for Inhibition of Human Anion Transporter SLC26A6/PAT-1

PAT-1, encoded by the gene SLC26A6, is an exchanger of small organic and inorganic anions including oxalate and chloride in the kidney and the intestines. PAT-1 dysfunction is implicated in nephrolithiasis and hyperoxaluria, and its modulation is a potential therapeutic strategy to treat cystic fibrosis. PAT-1 has two small molecule inhibitors: DIDS, a non-specific anion exchanger inhibitor; and PAT1inh-B01 which is highly specific to PAT-1. In this study, we report high-resolution cryo-electron microscopy structures of the human PAT-1 homodimer in complex with these inhibitors to reveal their different inhibition mechanisms. These structures also uncover the complex interactions between the transmembrane, STAS and N-terminal domains, with implications on its ion exchange function. Hence, this study provides mechanistic insight into PAT-1 molecular function and inhibition, and contributes to our understanding of SLC26 transport mechanisms.

biochemistry↗