6awc
From Proteopedia
Structure of 30S ribosomal subunit and RNA polymerase complex in rotated state
Structural highlights
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Function[RS6_ECOLU] Binds together with S18 to 16S ribosomal RNA. [RS12_ECO45] With S4 and S5 plays an important role in translational accuracy.[HAMAP-Rule:MF_00403] 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] [RPOA_ECO57] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. [RS17_ECO45] One of the primary rRNA binding proteins, it binds specifically to the 5'-end of 16S ribosomal RNA. [RS13_ECO57] Located at the top of the head of the 30S subunit, it contacts several helices of the 16S rRNA. In the E.coli 70S ribosome in the initiation state it has been modeled to contact the 23S rRNA (bridge B1a) and protein L5 of the 50S subunit (bridge B1b), connecting the 2 subunits; bridge B1a is broken in the model with bound EF-G, while the protein-protein contacts between S13 and L5 in B1b change. Contacts the tRNAs in the A and P sites (By similarity). [RS18_ECO45] 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. [RS11_ECO45] Located on the platform of the 30S subunit, it bridges several disparate RNA helices of the 16S rRNA. Forms part of the Shine-Dalgarno cleft in the 70S ribosome. [RS8_ECO45] 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. [RS20_ECO45] Binds directly to 16S ribosomal RNA. [RPOB_ECO45] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. [RS4_ECO45] One of the primary rRNA binding proteins, it binds directly to 16S rRNA where it nucleates assembly of the body of the 30S subunit. With S5 and S12 plays an important role in translational accuracy. [RS7_ECO45] One of the primary rRNA binding proteins, it binds directly to 16S rRNA where it nucleates assembly of the head domain of the 30S subunit. Is located at the subunit interface close to the decoding center, probably blocks exit of the E-site tRNA. [RS15_ECO45] 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. Forms an intersubunit bridge (bridge B4) with the 23S rRNA of the 50S subunit in the ribosome. [RS10_ECO45] Involved in the binding of tRNA to the ribosomes. [RS3_ECO45] Binds the lower part of the 30S subunit head. Binds mRNA in the 70S ribosome, positioning it for translation. [RPOC_ECO57] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. [RS19_ECO45] Protein S19 forms a complex with S13 that binds strongly to the 16S ribosomal RNA. [RS14_ECO45] 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. [RS5_ECO57] With S4 and S12 plays an important role in translational accuracy. Located at the back of the 30S subunit body where it stabilizes the conformation of the head with respect to the body. [RPOZ_ECO45] Promotes RNA polymerase assembly. Latches the N- and C-terminal regions of the beta' subunit thereby facilitating its interaction with the beta and alpha subunits. Publication Abstract from PubMedIn bacteria, mRNA transcription and translation are coupled to coordinate optimal gene expression and maintain genome stability. Coupling is thought to involve direct interactions between RNA polymerase (RNAP) and the translational machinery. We present cryo-EM structures of E. coli RNAP core bound to the small ribosomal 30S subunit. The complex is stable under cell-like ionic conditions, consistent with functional interaction between RNAP and the 30S subunit. The RNA exit tunnel of RNAP aligns with the Shine-Dalgarno-binding site of the 30S subunit. Ribosomal protein S1 forms a wall of the tunnel between RNAP and the 30S subunit, consistent with its role in directing mRNAs onto the ribosome. The nucleic-acid-binding cleft of RNAP samples distinct conformations, suggesting different functional states during transcription-translation coupling. The architecture of the 30S*RNAP complex provides a structural basis for co-localization of the transcriptional and translational machineries, and inform future mechanistic studies of coupled transcription and translation. Structure of RNA polymerase bound to ribosomal 30S subunit.,Demo G, Rasouly A, Vasilyev N, Svetlov V, Loveland AB, Diaz-Avalos R, Grigorieff N, Nudler E, Korostelev AA Elife. 2017 Oct 13;6. pii: e28560. doi: 10.7554/eLife.28560. PMID:29027901[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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