Deletion of Ribosomal Cofactor Rimp Disrupts Late Stage 30S Subunit Assembly

Abstract

The bacterial 70S ribosome, consisting of the 30S and 50S subunits, facilitates protein synthesis and is a target for antibiotics. During 30S biogenesis, 16S ribosomal ribonucleic acid (rRNA) is co-transcriptionally processed by ribonucleases, and bound by ribosomal proteins (RPs) and cofactors. However, the coordination between rRNA processing, and cofactor and RP binding is unclear. Here, we reveal that deletion of the ribosomal cofactor gene, rimP, disrupts binding of specific RPs (S2, S12, S21) during the late stages of 30S assembly in Escherichia coli. We use a stable isotope labeling/mass spectrometry approach to show that the rimP deletion strain accumulates 30S assembly intermediates lacking the late assembly binders, S2, S12 and S21, with a marked delay in 30S assembly relative to 50S assembly. Further studies will determine the extent of rRNA processing in 30S assembly intermediates in the rimP deletion strain, towards elucidating the coordination between rRNA processing, RP binding and cofactor function.