2026/01/19 by Amos J. Nissley, Madison C Williams, Yekaterina Shulgina +3 · 1 voice
Biochemistry, Genetics and Molecular Biology · #RNA and protein synthesis mechanisms #RNA modifications and cancer #Bacterial Genetics and Biotechnology
paper · doi:10.64898/2026.01.19.700200
ABSTRACT Under nutrient limitation or stress, ribosome hibernation factors inactivate and protect ribosomes. Although ribosome hibernation plays an important role in microbes, we lack a complete understanding of this process in archaea. Here, we identify a family of hibernation factors, which we designate as single ribosomal subunit inhibitors (SriA-SriD), from the methanogenic archaeon Methanosarcina acetivorans . All four sri genes are encoded in an operon and each Sri protein inhibits protein synthesis in vitro . Deletion of sri genes in M. acetivorans impaired growth recovery after prolonged stationary phase and also led to depletion of the small ribosomal subunit. Cryo-EM structures show that Sri proteins bind to the ribosome in tandem and form conserved protein-protein interfaces. Sri is broadly distributed across archaeal phyla and sri genes frequently co-occur. Together, these findings establish Sri proteins as a distinct group of hibernation factors that protect ribosomes during dormancy and expand our understanding of ribosome hibernation in archaea.