5o60
Structure of the 50S large ribosomal subunit from Mycobacterium smegmatisStructure of the 50S large ribosomal subunit from Mycobacterium smegmatis
Structural highlights
Function[RL22_MYCS2] This protein binds specifically to 23S rRNA; its binding is stimulated by other ribosomal proteins, e.g. L4, L17, and L20. It is important during the early stages of 50S assembly. It makes multiple contacts with different domains of the 23S rRNA in the assembled 50S subunit and ribosome (By similarity).[HAMAP-Rule:MF_01331] The globular domain of the protein is located near the polypeptide exit tunnel on the outside of the subunit, while an extended beta-hairpin is found that lines the wall of the exit tunnel in the center of the 70S ribosome.[HAMAP-Rule:MF_01331] [RL5_MYCS2] This is 1 of the proteins that binds and probably mediates the attachment of the 5S RNA into the large ribosomal subunit, where it forms part of the central protuberance. In the 70S ribosome it contacts protein S13 of the 30S subunit (bridge B1b), connecting the 2 subunits; this bridge is implicated in subunit movement. Contacts the P site tRNA; the 5S rRNA and some of its associated proteins might help stabilize positioning of ribosome-bound tRNAs.[HAMAP-Rule:MF_01333] [A0QSG5_MYCS2] This is one of the proteins that binds and probably mediates the attachment of the 5S RNA into the large ribosomal subunit, where it forms part of the central protuberance.[HAMAP-Rule:MF_01337] [RL19_MYCS2] This protein is located at the 30S-50S ribosomal subunit interface and may play a role in the structure and function of the aminoacyl-tRNA binding site. [RL21_MYCS2] This protein binds to 23S rRNA in the presence of protein L20.[HAMAP-Rule:MF_01363] [A0QSG8_MYCS2] Binds to the 23S rRNA.[HAMAP-Rule:MF_01341][SAAS:SAAS00687840] [A0R3D2_MYCS2] This is one of the proteins that binds to the 5S RNA in the ribosome where it forms part of the central protuberance.[HAMAP-Rule:MF_01334][SAAS:SAAS00720025] [RL10_MYCS2] Forms part of the ribosomal stalk, playing a central role in the interaction of the ribosome with GTP-bound translation factors. [RL11_MYCS2] Forms part of the ribosomal stalk which helps the ribosome interact with GTP-bound translation factors.[HAMAP-Rule:MF_00736] [RL23_MYCS2] One of the early assembly proteins it binds 23S rRNA. One of the proteins that surrounds the polypeptide exit tunnel on the outside of the ribosome. Forms the main docking site for trigger factor binding to the ribosome.[HAMAP-Rule:MF_01369] [RL14_MYCS2] Binds to 23S rRNA. Forms part of two intersubunit bridges in the 70S ribosome. [RL24_MYCS2] One of two assembly initiator proteins, it binds directly to the 5'-end of the 23S rRNA, where it nucleates assembly of the 50S subunit. One of the proteins that surrounds the polypeptide exit tunnel on the outside of the subunit. [RL4_MYCS2] One of the primary rRNA binding proteins, this protein initially binds near the 5'-end of the 23S rRNA. It is important during the early stages of 50S assembly. It makes multiple contacts with different domains of the 23S rRNA in the assembled 50S subunit and ribosome.[HAMAP-Rule:MF_01328] Forms part of the polypeptide exit tunnel.[HAMAP-Rule:MF_01328] [RL9_MYCS2] Binds to the 23S rRNA. [RL13_MYCS2] This protein is one of the early assembly proteins of the 50S ribosomal subunit, although it is not seen to bind rRNA by itself. It is important during the early stages of 50S assembly.[HAMAP-Rule:MF_01366] [RL16_MYCS2] Binds 23S rRNA and is also seen to make contacts with the A and possibly P site tRNAs. [RL6_MYCS2] This protein binds to the 23S rRNA, and is important in its secondary structure. It is located near the subunit interface in the base of the L7/L12 stalk, and near the tRNA binding site of the peptidyltransferase center. [RL2_MYCS2] One of the primary rRNA binding proteins. Required for association of the 30S and 50S subunits to form the 70S ribosome, for tRNA binding and peptide bond formation. It has been suggested to have peptidyltransferase activity; this is somewhat controversial. Makes several contacts with the 16S rRNA in the 70S ribosome. [RL31_MYCS2] Binds the 23S rRNA. [RL20_MYCS2] Binds directly to 23S ribosomal RNA and is necessary for the in vitro assembly process of the 50S ribosomal subunit. It is not involved in the protein synthesizing functions of that subunit. [RL3_MYCS2] One of the primary rRNA binding proteins, it binds directly near the 3'-end of the 23S rRNA, where it nucleates assembly of the 50S subunit. Publication Abstract from PubMedThe ribosome carries out the synthesis of proteins in every living cell. It consequently represents a frontline target in anti-microbial therapy. Tuberculosis ranks among the leading causes of death worldwide, due in large part to the combination of difficult-to-treat latency and antibiotic resistance. Here, we present the 3.3-A cryo-EM structure of the 70S ribosome of Mycobacterium smegmatis, a close relative to the human pathogen Mycobacterium tuberculosis. The structure reveals two additional ribosomal proteins and localizes them to the vicinity of drug-target sites in both the catalytic center and the decoding site of the ribosome. Furthermore, we visualized actinobacterium-specific rRNA and protein expansions that extensively remodel the ribosomal surface with implications for polysome organization. Our results provide a foundation for understanding the idiosyncrasies of mycobacterial translation and reveal atomic details of the structure that will facilitate the design of anti-tubercular therapeutics. The Complete Structure of the Mycobacterium smegmatis 70S Ribosome.,Hentschel J, Burnside C, Mignot I, Leibundgut M, Boehringer D, Ban N Cell Rep. 2017 Jul 5;20(1):149-160. doi: 10.1016/j.celrep.2017.06.029. PMID:28683309[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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