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5no2
From Proteopedia
RsgA-GDPNP bound to the 30S ribosomal subunit (RsgA assembly intermediate)
Structural highlights
FunctionRS4_ECOLI One of two assembly initiator proteins for the 30S subunit, it binds directly to 16S rRNA where it nucleates assembly of the body of the 30S subunit.[1] [2] [3] With S5 and S12 plays an important role in translational accuracy; many suppressors of streptomycin-dependent mutants of protein S12 are found in this protein, some but not all of which decrease translational accuracy (ram, ribosomal ambiguity mutations).[4] [5] [6] Plays a role in mRNA unwinding by the ribosome, possibly by forming part of a processivity clamp.[7] [8] [9] Protein S4 is also a translational repressor protein, it controls the translation of the alpha-operon (which codes for S13, S11, S4, RNA polymerase alpha subunit, and L17) by binding to its mRNA.[10] [11] [12] Also functions as a rho-dependent antiterminator of rRNA transcription, increasing the synthesis of rRNA under conditions of excess protein, allowing a more rapid return to homeostasis. Binds directly to RNA polymerase.[13] [14] [15] Publication Abstract from PubMedDuring 30S ribosomal subunit biogenesis, assembly factors are believed to prevent accumulation of misfolded intermediate states of low free energy that slowly convert into mature 30S subunits, namely, kinetically trapped particles. Among the assembly factors, the circularly permuted GTPase, RsgA, plays a crucial role in the maturation of the 30S decoding center. Here, directed hydroxyl radical probing and single particle cryo-EM are employed to elucidate RsgA's mechanism of action. Our results show that RsgA destabilizes the 30S structure, including late binding r-proteins, providing a structural basis for avoiding kinetically trapped assembly intermediates. Moreover, RsgA exploits its distinct GTPase pocket and specific interactions with the 30S to coordinate GTPase activation with the maturation state of the 30S subunit. This coordination validates the architecture of the decoding center and facilitates the timely release of RsgA to control the progression of 30S biogenesis. RsgA couples the maturation state of the 30S ribosomal decoding center to activation of its GTPase pocket.,Lopez-Alonso JP, Kaminishi T, Kikuchi T, Hirata Y, Iturrioz I, Dhimole N, Schedlbauer A, Hase Y, Goto S, Kurita D, Muto A, Zhou S, Naoe C, Mills DJ, Gil-Carton D, Takemoto C, Himeno H, Fucini P, Connell SR Nucleic Acids Res. 2017 May 8. doi: 10.1093/nar/gkx324. PMID:28482099[16] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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Categories: Escherichia coli K-12 | Large Structures | Connell SR | Dhimole N | Fucini P | Gil-Carton D | Goto S | Hase Y | Himeno H | Hirata Y | Iturrioz I | Kaminishi T | Kikuchi T | Kurita D | Lopez-Alonso JP | Mills DJ | Muto A | Naoe C | Schedlbauer A | Takemoto C | Zhou S
