9p4i
YsxC-GTP treated 44.5SYsxC particles. Class 5.
Structural highlights
FunctionA0A063XCB6_BACIU One of the primary rRNA binding proteins. Required for association of the 30S and 50S subunits to form the 70S ribosome, for tRNA binding and peptide bond formation. It has been suggested to have peptidyltransferase activity; this is somewhat controversial. Makes several contacts with the 16S rRNA in the 70S ribosome.[HAMAP-Rule:MF_01320] Publication Abstract from PubMedThe maturation of the functional core of the 50S ribosomal subunit in Bacillus subtilis is assisted by assembly factors that enhance the efficiency of the process. Two essential assembly factors, the GTPases RbgA and YphC, bind at or near the functional sites of the 50S subunit to promote the folding of ribosomal RNA helices that play key functional roles. YsxC is another GTPase involved in the maturation of the 50S subunit, whose function remains unknown. We demonstrate that YsxC aids 50S assembly through a drastically different mechanism. YsxC binds in the body of the 44.5S large ribosome assembly intermediate, occupying the site where uL2 binds and controls the timing in the folding of rRNA helices forming the binding site for uL2. It creates a "primordial" binding site that includes six out of the eleven rRNA helices forming the uL2 mature binding site. Once YsxC is released, uL2 binds to this "primordial" binding site, and the remaining helices that stabilize uL2 fold, and the entire region adopts the mature conformation. This role of YsxC functioning as a placeholder factor for ribosomal protein uL2 provides the first example of such a factor's involvement in the ribosome assembly process in bacteria. YsxC is a placeholder for ribosomal protein uL2 during 50S ribosomal subunit assembly.,Seffouh A, Arpin D, Basu K, Ortega J Nucleic Acids Res. 2025 Oct 28;53(20):gkaf1071. doi: 10.1093/nar/gkaf1071. PMID:41148149[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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