2uxb
From Proteopedia
Crystal structure of an extended tRNA anticodon stem loop in complex with its cognate mRNA GGGU in the context of the Thermus thermophilus 30S subunit.
Structural highlights
FunctionRS7_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] 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 PubMedDuring translation, some +1 frameshift mRNA sites are decoded by frameshift suppressor tRNAs that contain an extra base in their anticodon loops. Similarly engineered tRNAs have been used to insert nonnatural amino acids into proteins. Here, we report crystal structures of two anticodon stem-loops (ASLs) from tRNAs known to facilitate +1 frameshifting bound to the 30S ribosomal subunit with their cognate mRNAs. ASL(CCCG) and ASL(ACCC) (5'-3' nomenclature) form unpredicted anticodon-codon interactions where the anticodon base 34 at the wobble position contacts either the fourth codon base or the third and fourth codon bases. In addition, we report the structure of ASL(ACGA) bound to the 30S ribosomal subunit with its cognate mRNA. The tRNA containing this ASL was previously shown to be unable to facilitate +1 frameshifting in competition with normal tRNAs (Hohsaka et al. 2001), and interestingly, it displays a normal anticodon-codon interaction. These structures show that the expanded anticodon loop of +1 frameshift promoting tRNAs are flexible enough to adopt conformations that allow three bases of the anticodon to span four bases of the mRNA. Therefore it appears that normal triplet pairing is not an absolute constraint of the decoding center. Structures of tRNAs with an expanded anticodon loop in the decoding center of the 30S ribosomal subunit.,Dunham CM, Selmer M, Phelps SS, Kelley AC, Suzuki T, Joseph S, Ramakrishnan V RNA. 2007 Jun;13(6):817-23. Epub 2007 Apr 6. PMID:17416634[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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