Mapping of protein positions in the ribosomal subunits was first achieved for the 30S subunit by means of neutron scattering about 15 years ago. Since the 50S subunit is almost twice as large as the 30S subunit and consists of more proteins, it was difficult to apply classical contrast variation techniques for the localisation of the proteins. Polarisation dependent neutron scattering (spin-contrast variation) helped to overcome this restriction. Here a map of 14 proteins within the 50S subunit from Escherichia coli ribosomes is presented including the proteins L17 and L20 that are not present in archeal ribosomes. The results are compared with the recent crystallographic map of the 50S subunit from the archea Haloarcula marismortui.
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http://dx.doi.org/10.1016/s0167-4781(01)00245-7 | DOI Listing |
The sarcin-ricin loop (SRL) is one of the most conserved segments of ribosomal RNA (rRNA). Translational GTPases (trGTPases), such as EF-G and EF-Tu and IF2, form contacts with the SRL that are critical for GTP hydrolysis and factor function. Previous studies showed that expression of 23S rRNA lacking the SRL confers a dominant lethal phenotype in E.
View Article and Find Full Text PDFJ Med Chem
January 2025
Xi'an Key Laboratory for Antiviral and Antimicrobial-Resistant Bacteria Therapeutics Research, Xi'an 710021, China.
Multidrug-resistant (MDR) bacteria pose a global health threat, underscoring the need for new antibiotics. Lefamulin, the first novel-mechanism antibiotic approved by the FDA in decades, showcases pleuromutilins' promise due to low mutation frequency. However, their clinical use is limited by poor pharmacokinetics and organ toxicity.
View Article and Find Full Text PDFNat Commun
January 2025
Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Universität Leipzig, Leipzig, Germany.
The proline-rich antimicrobial designer peptide Api137 inhibits protein expression in bacteria by binding simultaneously to the ribosomal polypeptide exit tunnel and the release factor (RF), depleting the cellular RF pool and leading to ribosomal arrest at stop codons. This study investigates the additional effect of Api137 on the assembly of ribosomes using an Escherichia coli reporter strain expressing one ribosomal protein per 30S and 50S subunit tagged with mCherry and EGFP, respectively. Separation of cellular extracts derived from cells exposed to Api137 in a sucrose gradient reveals elevated levels of partially assembled and not fully matured precursors of the 50S subunit (pre-50S).
View Article and Find Full Text PDFJ Biomol Struct Dyn
January 2025
Department of Studies in Physics, University of Mysore, Mysuru, India.
Nucleic Acids Res
January 2025
Department of Anatomy and Cell Biology, McGill University, 3640 Rue University, Montreal, Quebec H3A 0C7, Canada.
The intricate process of 50S ribosomal subunit assembly in Bacillus subtilis involves multiple parallel pathways converging into a crucial intermediate known as the 45S particle. RbgA and YphC, play pivotal roles in completing the maturation of the functional sites in the 45S particle. In this work, we found that RbgA and YphC can independently bind the 45S particle with high affinity, but when RbgA binds first to the particle, it significantly increases the binding affinity of YphC.
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