8EYQ

30S_delta_ksgA_h44_inactive_conformation

Summary for 8EYQ

• Entry DOI: 10.2210/pdb8eyq/pdb
• EMDB information: 28692
• Descriptor: 30S ribosomal protein S4, 30S ribosomal protein S18, 30S ribosomal protein S20, ... (18 entities in total)
• Functional Keywords: ribosome, ksga
• Biological source: Escherichia coli; More
• Total number of polymer chains: 18
• Total formula weight: 733525.80

Authors

Ortega, J.,Sun, J. (deposition date: 2022-10-28, release date: 2023-09-06, Last modification date: 2023-11-01)

Primary citation

Sun, J.,Kinman, L.F.,Jahagirdar, D.,Ortega, J.,Davis, J.H.
KsgA facilitates ribosomal small subunit maturation by proofreading a key structural lesion.
Nat.Struct.Mol.Biol., 30:1468-1480, 2023

PubMed Abstract: Ribosome assembly is orchestrated by many assembly factors, including ribosomal RNA methyltransferases, whose precise role is poorly understood. Here, we leverage the power of cryo-EM and machine learning to discover that the E. coli methyltransferase KsgA performs a 'proofreading' function in the assembly of the small ribosomal subunit by recognizing and partially disassembling particles that have matured but are not competent for translation. We propose that this activity allows inactive particles an opportunity to reassemble into an active state, thereby increasing overall assembly fidelity. Detailed structural quantifications in our datasets additionally enabled the expansion of the Nomura assembly map to highlight rRNA helix and r-protein interdependencies, detailing how the binding and docking of these elements are tightly coupled. These results have wide-ranging implications for our understanding of the quality-control mechanisms governing ribosome biogenesis and showcase the power of heterogeneity analysis in cryo-EM to unveil functionally relevant information in biological systems.

PubMed: 37653244
DOI: 10.1038/s41594-023-01078-5

Experimental method

ELECTRON MICROSCOPY (3.3 Å)