[RS15_ECOLI] 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.[HAMAP-Rule:MF_01343] In the E.coli 70S ribosome it has been modeled (PubMed:12809609) to contact the 23S rRNA of the 50S subunit forming part of bridge B4. In the two 3.5 A resolved ribosome structures (PubMed:16272117) there are minor differences between side-chain conformations.[HAMAP-Rule:MF_01343]
Evolutionary Conservation
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Publication Abstract from PubMed
Gene expression can be regulated at the level of initiation of protein biosynthesis via structural elements present at the 5' untranslated region of mRNAs. These folded mRNA segments may bind to the ribosome, thus blocking translation until the mRNA unfolds. Here, we report a series of cryo-electron microscopy snapshots of ribosomal complexes directly visualizing either the mRNA structure blocked by repressor protein S15 or the unfolded, active mRNA. In the stalled state, the folded mRNA prevents the start codon from reaching the peptidyl-tRNA (P) site inside the ribosome. Upon repressor release, the mRNA unfolds and moves into the mRNA channel allowing translation initiation. A comparative structure and sequence analysis suggests the existence of a universal stand-by site on the ribosome (the 30S platform) dedicated for binding regulatory 5' mRNA elements. Different types of mRNA structures may be accommodated during translation preinitiation and regulate gene expression by transiently stalling the ribosome.
Structured mRNAs regulate translation initiation by binding to the platform of the ribosome.,Marzi S, Myasnikov AG, Serganov A, Ehresmann C, Romby P, Yusupov M, Klaholz BP Cell. 2007 Sep 21;130(6):1019-31. PMID:17889647[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
↑Marzi S, Myasnikov AG, Serganov A, Ehresmann C, Romby P, Yusupov M, Klaholz BP. Structured mRNAs regulate translation initiation by binding to the platform of the ribosome. Cell. 2007 Sep 21;130(6):1019-31. PMID:17889647 doi:10.1016/j.cell.2007.07.008
