Anticodon nucleotide modifications affect translational tuning by the ribosomal CAR surface

Nucleotide modifications of the tRNA anticodon can affect protein translation fidelity and speed. Chemical modifications of the anticodon nucleotide 34 are regulated under cellular stress and associat...

biorxiv.org

A p32 family RNA editing factor acts in mitochondrial ribosome biogenesis

Biogenesis of mitochondrial ribosomes (mitoribosomes) in the unicellular parasite Trypanosoma brucei requires an exceptionally large toolkit of assembly factors, identified in stable precursors of lar...

biorxiv.org

Reassigning an amber codon to selenocysteine using a functional cysteine suppression pair in Escherichia coli

Selenoproteins, characterized by the presence of selenocysteine (Sec) residues, are widely distributed across all domains of life. The unique attribut…

sciencedirect.com

Dietary arginine drives codon-dependent MHC class I translation and improves immunity in colon tumorigenesis and respiratory viral infection

Arginine availability regulates arginyl tRNA levels and codon-dependent translation of MHC class I, tuning antigen presentation and shaping anti-viral and anti-tumor immunity.

cell.com

A tRNA as an Architectural Scaffold in the Trypanosome Editosome

A transfer RNA (tRNA) was originally seen as a boring adaptor that brings amino acids to the ribosome during protein translation. A tRNA, with its distinct 2D cloverleaf structure, has an amino aci…

rnastuff.com

Mitochondrial tRNA biogenesis, modifications and disease relevance

Nature Reviews Molecular Cell Biology, Published online: 24 July 2026; doi:10.1038/s41580-026-00999-5Mitochondrial tRNA (mt-tRNA) biogenesis has evolved to support a degenerate mt-tRNA structure and a simplified genetic code. Liu and colleagues provide a fascinating overview of mt-tRNA biology, discuss how mt-tRNA-associated perturbations directly cause disease, and examine how emerging knowledge will lead to targeted therapeutics.

dlvr.it

Structural basis of the RNA-editing cascade in trypanosome mitochondria - Nature

Cryo-electron microscopy sheds light on the architecture of the Trypanosoma brucei mitochondrial editosome and reveals how this assembly mediates mRNA editing through the insertion and deletion of uri...

nature.com

Cryo-EM reveals that Escherichia coli tRNA-transglycosylase can bind and act upon two tRNAs | PNAS

Bacterial tRNA-guanine transglycosylases (TGT) are essential enzymes involved in tRNA modification, contributing to the virulence of multiple patho...

pnas.org

Structural basis for emetine inhibition of ribosome translocation in Toxoplasma gondii

Apicomplexan parasites, including Toxoplasma gondii and Plasmodium falciparum, are major human pathogens that cause toxoplasmosis and malaria, respectively. The existing structures of T. gondii translational machinery are from empty ribosomes that lack several key components, including ribosomal protein RACK1 (Receptor for Activated C Kinase 1). Here, we used cryo-electron microscopy (cryoEM) to determine high-resolution structures of T. gondii ribosomal complexes, including a translating 80S ribosome bound to mRNA and tRNA. These structures reveal that RACK1 occupies the conserved binding site on the 40S subunit observed in other eukaryotic ribosomes. We also determined the architecture of the ribosomal P-stalk and identified the ribosomal proteins uL10 and uL11, which were not observed in previous T. gondii ribosome structures. In addition, we determined structures of the 80S ribosome bound to mRNA, tRNA, and the translation inhibitor emetine in two distinct conformational states. These snapshots reveal two mechanisms by which emetine inhibits the translocation step of mRNA translation: either by dislodging the mRNA from the E-site of the ribosome or by acting as a molecular glue within the E-site, thereby stalling translocation. Together, these findings provide new insights into the molecular basis of protein synthesis in apicomplexan parasites and establish a structural framework for the development of future antiparasitic therapeutics.

dlvr.it

Trypanosomal MICOS is assembled on non-respiring mitochondrial crista precursors and associates with two integral microproteins

The mitochondrial contact site and cristae organizing system (MICOS) is a multiprotein complex that shapes crista junctions and maintains inner and outer membrane contacts. MICOS coordinates the assembly of electron transport chain complexes, a prerequisite for cellular respiration. Indeed, MICOS is lost in eukaryotes that dispensed with cellular respiration, suggesting that its assembly depends on the presence of an active respiratory chain. Trypanosoma brucei provides a unique system to test this hypothesis as its mitochondrion undergoes developmentally regulated remodeling. In the insect stage, the mitochondrion contains cristae with an active electron transport chain, whereas the mammalian bloodstream form possesses precursor cristae with stub-like morphology that lack respiratory activity. MICOS has been characterized in the insect stage but remains unexamined in the bloodstream form. Here, we demonstrate that all MICOS subunits assemble onto precursor cristae, retaining conserved interactions with both outer and inner membrane protein machineries. This is somewhat unexpected given the co-occurrence of MICOS with active cellular respiration in nature. Furthermore, we identify novel MICOS-associated proteins that are dispensable for its stability, suggesting auxiliary rather than core roles in MICOS function. Together, our findings establish that MICOS assembly precedes cellular respiratory competence and expand its interaction landscape in trypanosomatids.

dlvr.it

Profiling of terminating ribosomes reveals translational control at stop codons

Systematic characterization of terminating ribosomes uncovers sequence features influencing ribosome dynamics at stop codons with direct implications in 3' UTR translation.

elifesciences.org

The Invisible Education of PhD Life

Over dinner with a distinguished parasitologist, our PI told us that something very important about science is that it makes you meet very interesting people. The formal PhD experience is generally…

rnastuff.com

A symbiotic origin of the ribosome?

Abstract. The origin of life is one of the great mysteries of science. Of the multiple unsolved problems, the origin of the translation system (the means b

academic.oup.com

New tool decodes the structures and motifs of RNA

nachrichten.idw-online.de

Comparative Genomics, and the Boundaries of Molecular Rules

The evolution of life on Earth is a history of countless successes and failures. The variations arise through chance, but within physical, chemical, and biological organization and limitations. Nat…

rnastuff.com

biorxiv.org

DRT3 and the Creativity of Molecular Biology

A recent Science paper described an extremely strange antiphage reverse transcriptase system, DRT3. DRT3 is made up of two RT-like proteins, DRT3a and DRT3b, and a non-coding RNA. These assemble in…

rnastuff.com

Frequent occurrence and predicted functions of tRNAs with 4-base-pair anticodon stems in bacteria: extended superwobble hypothesis

Abstract. Recently, a tRNATrpCCA with a 4-base-pair (bp) anticodon stem (AS) was shown to efficiently recognize a near-cognate UGA codon in unicellular euk

academic.oup.com

The 4-bp anticodon stem tRNA: an anarchist of the genetic code

In our genetics 101, we often learn that the genetic code is a strict dictionary. But biology, as we know it, is the wonderland of exceptions. In fact, the genetic code can only be called “nearly u…

rnastuff.com

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academic.oup.com

Subcellular proteomics reveals a blueprint for endosymbiont integration in trypanosomatid Angomonas deanei - Nature Communications

The flagellated protist Angomonas deanei harbours a bacterial endosymbiont. Here, Hammond et al. report a high-confidence subcellular proteome, localising 5,796 proteins of the protist and its endosym...

nature.com

Why evolution needs noise: in the light of QT45 ribozyme

A violet amethyst crystal, while beautiful on the outside, is a highly ordered structure at the microscopic level, and therefore cannot evolve. In contrast, a gas is highly random and cannot store …

rnastuff.com