Structural highlightsFunctionRS4_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 PubMed
Ribosome biogenesis is a highly coordinated and complex process that requires numerous assembly factors that ensure prompt and flawless maturation of ribosomal subunits. Despite the increasing amount of data collected, the exact role of most assembly factors and mechanistic details of their operation remain unclear, mainly due to the shortage of high-resolution structural information. Here, using cryo-electron microscopy, we characterized 30S ribosomal particles isolated from an Escherichia coli strain with a deleted gene for the RbfA factor. The cryo-EM maps for pre-30S subunits were divided into six classes corresponding to consecutive assembly intermediates: from the particles with a completely unresolved head domain and unfolded central pseudoknot to almost mature 30S subunits with well-resolved body, platform, and head domains and partially distorted helix 44. The structures of two predominant 30S intermediates belonging to most populated classes obtained at 2.7 A resolutions indicate that RbfA acts at two distinctive 30S assembly stages: early formation of the central pseudoknot including folding of the head, and positioning of helix 44 in the decoding center at a later stage. Additionally, it was shown that the formation of the central pseudoknot may promote stabilization of the head domain, likely through the RbfA-dependent maturation of the neck helix 28. An update to the model of factor-dependent 30S maturation is proposed, suggesting that RfbA is involved in most of the subunit assembly process.
RbfA Is Involved in Two Important Stages of 30S Subunit Assembly: Formation of the Central Pseudoknot and Docking of Helix 44 to the Decoding Center.,Maksimova EM, Korepanov AP, Kravchenko OV, Baymukhametov TN, Myasnikov AG, Vassilenko KS, Afonina ZA, Stolboushkina EA Int J Mol Sci. 2021 Jun 7;22(11):6140. doi: 10.3390/ijms22116140. PMID:34200244[16]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See AlsoReferences
- ↑ Nowotny V, Nierhaus KH. Assembly of the 30S subunit from Escherichia coli ribosomes occurs via two assembly domains which are initiated by S4 and S7. Biochemistry. 1988 Sep 6;27(18):7051-5. PMID:2461734
- ↑ Torres M, Condon C, Balada JM, Squires C, Squires CL. Ribosomal protein S4 is a transcription factor with properties remarkably similar to NusA, a protein involved in both non-ribosomal and ribosomal RNA antitermination. EMBO J. 2001 Jul 16;20(14):3811-20. PMID:11447122 doi:10.1093/emboj/20.14.3811
- ↑ Takyar S, Hickerson RP, Noller HF. mRNA helicase activity of the ribosome. Cell. 2005 Jan 14;120(1):49-58. PMID:15652481 doi:10.1016/j.cell.2004.11.042
- ↑ Nowotny V, Nierhaus KH. Assembly of the 30S subunit from Escherichia coli ribosomes occurs via two assembly domains which are initiated by S4 and S7. Biochemistry. 1988 Sep 6;27(18):7051-5. PMID:2461734
- ↑ Torres M, Condon C, Balada JM, Squires C, Squires CL. Ribosomal protein S4 is a transcription factor with properties remarkably similar to NusA, a protein involved in both non-ribosomal and ribosomal RNA antitermination. EMBO J. 2001 Jul 16;20(14):3811-20. PMID:11447122 doi:10.1093/emboj/20.14.3811
- ↑ Takyar S, Hickerson RP, Noller HF. mRNA helicase activity of the ribosome. Cell. 2005 Jan 14;120(1):49-58. PMID:15652481 doi:10.1016/j.cell.2004.11.042
- ↑ Nowotny V, Nierhaus KH. Assembly of the 30S subunit from Escherichia coli ribosomes occurs via two assembly domains which are initiated by S4 and S7. Biochemistry. 1988 Sep 6;27(18):7051-5. PMID:2461734
- ↑ Torres M, Condon C, Balada JM, Squires C, Squires CL. Ribosomal protein S4 is a transcription factor with properties remarkably similar to NusA, a protein involved in both non-ribosomal and ribosomal RNA antitermination. EMBO J. 2001 Jul 16;20(14):3811-20. PMID:11447122 doi:10.1093/emboj/20.14.3811
- ↑ Takyar S, Hickerson RP, Noller HF. mRNA helicase activity of the ribosome. Cell. 2005 Jan 14;120(1):49-58. PMID:15652481 doi:10.1016/j.cell.2004.11.042
- ↑ Nowotny V, Nierhaus KH. Assembly of the 30S subunit from Escherichia coli ribosomes occurs via two assembly domains which are initiated by S4 and S7. Biochemistry. 1988 Sep 6;27(18):7051-5. PMID:2461734
- ↑ Torres M, Condon C, Balada JM, Squires C, Squires CL. Ribosomal protein S4 is a transcription factor with properties remarkably similar to NusA, a protein involved in both non-ribosomal and ribosomal RNA antitermination. EMBO J. 2001 Jul 16;20(14):3811-20. PMID:11447122 doi:10.1093/emboj/20.14.3811
- ↑ Takyar S, Hickerson RP, Noller HF. mRNA helicase activity of the ribosome. Cell. 2005 Jan 14;120(1):49-58. PMID:15652481 doi:10.1016/j.cell.2004.11.042
- ↑ Nowotny V, Nierhaus KH. Assembly of the 30S subunit from Escherichia coli ribosomes occurs via two assembly domains which are initiated by S4 and S7. Biochemistry. 1988 Sep 6;27(18):7051-5. PMID:2461734
- ↑ Torres M, Condon C, Balada JM, Squires C, Squires CL. Ribosomal protein S4 is a transcription factor with properties remarkably similar to NusA, a protein involved in both non-ribosomal and ribosomal RNA antitermination. EMBO J. 2001 Jul 16;20(14):3811-20. PMID:11447122 doi:10.1093/emboj/20.14.3811
- ↑ Takyar S, Hickerson RP, Noller HF. mRNA helicase activity of the ribosome. Cell. 2005 Jan 14;120(1):49-58. PMID:15652481 doi:10.1016/j.cell.2004.11.042
- ↑ Maksimova EM, Korepanov AP, Kravchenko OV, Baymukhametov TN, Myasnikov AG, Vassilenko KS, Afonina ZA, Stolboushkina EA. RbfA Is Involved in Two Important Stages of 30S Subunit Assembly: Formation of the Central Pseudoknot and Docking of Helix 44 to the Decoding Center. Int J Mol Sci. 2021 Jun 7;22(11):6140. PMID:34200244 doi:10.3390/ijms22116140
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