2hhh | pdb_00002hhh
Crystal structure of kasugamycin bound to the 30S ribosomal subunit
Structural highlights
Function[RS11_THET8] Located on the upper part of the platform of the 30S subunit, where it bridges several disparate RNA helices of the 16S rRNA. Forms part of the Shine-Dalgarno cleft in the 70S ribosome, where it interacts both with the Shine-Dalgarno helix and mRNA.[HAMAP-Rule:MF_01310] [RSHX_THETH] Binds at the top of the head of the 30S subunit. It stabilizes a number of different RNA elements and thus is important for subunit structure (By similarity). [RS7_THET8] One of the primary rRNA binding proteins, it binds directly to 3'-end of the 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. Binds mRNA and the E site tRNA blocking its exit path in the ribosome. This blockage implies that this section of the ribosome must be able to move to release the deacetylated tRNA.[HAMAP-Rule:MF_00480_B] [RS2_THET8] Spans the head-body hinge region of the 30S subunit. Is loosely associated with the 30S subunit.[HAMAP-Rule:MF_00291_B] [RS17_THETH] One of the primary rRNA binding proteins, it binds specifically to the 5'-end of 16S ribosomal RNA (By similarity). [RS18_THETH] 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 (By similarity). [RS13_THET8] Located at the top of the head of the 30S subunit, it contacts several helices of the 16S rRNA. In the 70S ribosome structure it contacts the 23S rRNA (bridge B1a) and protein L5 of the 50S subunit (bridge B1b), connecting the top of the two subunits; these bridges are in contact with the A site and P site tRNAs respectively and are implicated in movement during ribosome translocation. Separately contacts the tRNAs in the A and P sites.[HAMAP-Rule:MF_01315] [RS16_THET8] Binds to the lower part of the body of the 30S subunit, where it stabilizes two of its domains.[HAMAP-Rule:MF_00385] [RS6_THETH] Located on the outer edge of the platform on the body of the 30S subunit (By similarity). [RS3_THET8] Binds the lower part of the 30S subunit head. Binds mRNA in the 70S ribosome, positioning it for translation.[HAMAP-Rule:MF_01309_B] [RS9_THET8] Part of the top of the head of the 30S subunit. The C-terminal region penetrates the head emerging in the P-site where it contacts tRNA.[HAMAP-Rule:MF_00532_B] [RS12_THETH] With S4 and S5 plays an important role in translational accuracy (By similarity).[HAMAP-Rule:MF_00403_B] 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 (By similarity).[HAMAP-Rule:MF_00403_B] [RS14Z_THETH] 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 (By similarity). [RS15_THETH] 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 (By similarity). [RS20_THET8] One of the primary rRNA binding proteins, it binds directly to 16S rRNA where it nucleates assembly of the bottom of the body of the 30S subunit, by binding to several RNA helices of the 16S rRNA.[HAMAP-Rule:MF_00500] [RS8_THETH] 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 (By similarity). [RS4_THET8] One of the primary rRNA binding proteins, it binds directly to 16S rRNA where it helps nucleate assembly of the body and platform of the 30S subunit. Binds mRNA in the 70S ribosome, positioning it for translation.[HAMAP-Rule:MF_01306_B] [RS10_THETH] Involved in the binding of tRNA to the ribosomes (By similarity). [RS19_THETH] Protein S19 forms a complex with S13 that binds strongly to the 16S ribosomal RNA (By similarity). [RS5_THETH] With S4 and S12 plays an important role in translational accuracy (By similarity).[HAMAP-Rule:MF_01307_B] Located at the back of the 30S subunit body where it stabilizes the conformation of the head with respect to the body (By similarity).[HAMAP-Rule:MF_01307_B] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedKasugamycin (Ksg) specifically inhibits translation initiation of canonical but not of leaderless messenger RNAs. Ksg inhibition is thought to occur by direct competition with initiator transfer RNA. The 3.35-A structure of Ksg bound to the 30S ribosomal subunit presented here provides a structural description of two Ksg-binding sites as well as a basis for understanding Ksg resistance. Notably, neither binding position overlaps with P-site tRNA; instead, Ksg mimics codon nucleotides at the P and E sites by binding within the path of the mRNA. Coupled with biochemical experiments, our results suggest that Ksg indirectly inhibits P-site tRNA binding through perturbation of the mRNA-tRNA codon-anticodon interaction during 30S canonical initiation. In contrast, for 70S-type initiation on leaderless mRNA, the overlap between mRNA and Ksg is reduced and the binding of tRNA is further stabilized by the presence of the 50S subunit, minimizing Ksg efficacy. The antibiotic kasugamycin mimics mRNA nucleotides to destabilize tRNA binding and inhibit canonical translation initiation.,Schluenzen F, Takemoto C, Wilson DN, Kaminishi T, Harms JM, Hanawa-Suetsugu K, Szaflarski W, Kawazoe M, Shirouzu M, Nierhaus KH, Yokoyama S, Fucini P Nat Struct Mol Biol. 2006 Oct;13(10):871-8. Epub 2006 Sep 24. PMID:16998488[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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