6nqb
From Proteopedia
Role of Era in Assembly and Homeostasis of the Ribosomal Small Subunit
Structural highlights
Function[RS15_ECO57] One of the primary rRNA binding proteins, it binds directly to 16S rRNA where it helps nucleate assembly of the platform of the 30S subunit by binding and bridging several RNA helices of the 16S rRNA (By similarity). Forms an intersubunit bridge (bridge B4) with the 23S rRNA of the 50S subunit in the ribosome (By similarity). [D7X302_ECOLX] Involved in the binding of tRNA to the ribosomes.[HAMAP-Rule:MF_00508] [A0A376HTV6_ECOLX] Binds the lower part of the 30S subunit head. Binds mRNA in the 70S ribosome, positioning it for translation.[HAMAP-Rule:MF_01309] [A0A0G3QJD8_9GAMM] One of the primary rRNA binding proteins, it binds specifically to the 5'-end of 16S ribosomal RNA.[HAMAP-Rule:MF_01345] [L3PZ69_ECOLX] One of the primary rRNA binding proteins, it binds directly to 16S rRNA where it nucleates assembly of the body of the 30S subunit.[HAMAP-Rule:MF_01306] With S5 and S12 plays an important role in translational accuracy.[HAMAP-Rule:MF_01306] [A0A090BZT4_ECOLX] Binds 16S rRNA, required for the assembly of 30S particles and may also be responsible for determining the conformation of the 16S rRNA at the A site.[HAMAP-Rule:MF_00537] [D8A1L7_ECOMS] One of the primary rRNA binding proteins, it binds directly to 16S rRNA central domain where it helps coordinate assembly of the platform of the 30S subunit.[HAMAP-Rule:MF_01302] [D7ZI16_ECOLX] Binds as a heterodimer with protein S6 to the central domain of the 16S rRNA, where it helps stabilize the platform of the 30S subunit.[HAMAP-Rule:MF_00270] [T6N332_ECOLX] Binds directly to 16S ribosomal RNA.[HAMAP-Rule:MF_00500] [A0A074QGH8_ECOLX] Binds together with S18 to 16S ribosomal RNA.[HAMAP-Rule:MF_00360][SAAS:SAAS00348112] [F4SQ43_ECOLX] Protein S19 forms a complex with S13 that binds strongly to the 16S ribosomal RNA.[HAMAP-Rule:MF_00531] [V6FZ95_ECOLX] Interacts with and stabilizes bases of the 16S rRNA that are involved in tRNA selection in the A site and with the mRNA backbone. Located at the interface of the 30S and 50S subunits, it traverses the body of the 30S subunit contacting proteins on the other side and probably holding the rRNA structure together. The combined cluster of proteins S8, S12 and S17 appears to hold together the shoulder and platform of the 30S subunit.[HAMAP-Rule:MF_00403][RuleBase:RU003623] With S4 and S5 plays an important role in translational accuracy.[HAMAP-Rule:MF_00403][RuleBase:RU003623] Publication Abstract from PubMedAssembly factors provide speed and directionality to the maturation process of the 30S subunit in bacteria. To gain a more precise understanding of how these proteins mediate 30S maturation, it is important to expand on studies of 30S assembly intermediates purified from bacterial strains lacking particular maturation factors. To reveal the role of the essential protein Era in the assembly of the 30S ribosomal subunit, we analyzed assembly intermediates that accumulated in Era-depleted Escherichia coli cells using quantitative mass spectrometry, high resolution cryo-electron microscopy and in-cell footprinting. Our combined approach allowed for visualization of the small subunit as it assembled and revealed that with the exception of key helices in the platform domain, all other 16S rRNA domains fold even in the absence of Era. Notably, the maturing particles did not stall while waiting for the platform domain to mature and instead re-routed their folding pathway to enable concerted maturation of other structural motifs spanning multiple rRNA domains. We also found that binding of Era to the mature 30S subunit destabilized helix 44 and the decoding center preventing binding of YjeQ, another assembly factor. This work establishes Era's role in ribosome assembly and suggests new roles in maintaining ribosome homeostasis. Role of Era in assembly and homeostasis of the ribosomal small subunit.,Razi A, Davis JH, Hao Y, Jahagirdar D, Thurlow B, Basu K, Jain N, Gomez-Blanco J, Britton RA, Vargas J, Guarne A, Woodson SA, Williamson JR, Ortega J Nucleic Acids Res. 2019 Jul 2. pii: 5527280. doi: 10.1093/nar/gkz571. PMID:31265110[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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