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Binding of eIF3 in complex with eIF5 and eIF1 to the 40S ribosomal subunit is accompanied by dramatic structural changes
Zeman, Jakub
In eukaryotic translation, eukaryotic initiation factors (eIFs) are at least as important as the ribosome itself. Some of these factors play different roles throughout the entire process to ensure proper assembly of the preinitiation complex on mRNA, accurate selection of the initiation codon, errorless production of the encoded polypeptide and its proper termination. Perhaps, the most important factor integrating signals from others and coordinating their functions on the ribosome is eIF3. In Saccharomyces cerevisiae, eIF3 is formed by five subunits. All these subunits contain structural motifs responsible for contact with ribosomal proteins and RNAs. In addition to these highly structured parts, the rest of eIF3 is unstructured and very flexible. Therefore, despite the recent progress thanks to the use of a cryo-electron microscopy, a precise structure and position of eIF3 on the 40S ribosomal subunit are still not known. Also, the presence of eIF3 on 80S during early elongation and its role in reinitiation and readthrough are not fully understood. In order to crack mysteries of yeast eIF3, we used x-ray crystallography, chemical cross- linking coupled to mass spectrometry, and various biochemical and genetic assays. We demonstrated that eIF3 is very compactly packed when free in solution. This...
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Binding of eIF3 in complex with eIF5 and eIF1 to the 40S ribosomal subunit is accompanied by dramatic structural changes
Zeman, Jakub
In eukaryotic translation, eukaryotic initiation factors (eIFs) are at least as important as the ribosome itself. Some of these factors play different roles throughout the entire process to ensure proper assembly of the preinitiation complex on mRNA, accurate selection of the initiation codon, errorless production of the encoded polypeptide and its proper termination. Perhaps, the most important factor integrating signals from others and coordinating their functions on the ribosome is eIF3. In Saccharomyces cerevisiae, eIF3 is formed by five subunits. All these subunits contain structural motifs responsible for contact with ribosomal proteins and RNAs. In addition to these highly structured parts, the rest of eIF3 is unstructured and very flexible. Therefore, despite the recent progress thanks to the use of a cryo-electron microscopy, a precise structure and position of eIF3 on the 40S ribosomal subunit are still not known. Also, the presence of eIF3 on 80S during early elongation and its role in reinitiation and readthrough are not fully understood. In order to crack mysteries of yeast eIF3, we used x-ray crystallography, chemical cross- linking coupled to mass spectrometry, and various biochemical and genetic assays. We demonstrated that eIF3 is very compactly packed when free in solution. This...
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Binding of eIF3 in complex with eIF5 and eIF1 to the 40S ribosomal subunit is accompanied by dramatic structural changes
Zeman, Jakub ; Valášek, Leoš (advisor) ; Štefl, Richard (referee) ; Man, Petr (referee)
In eukaryotic translation, eukaryotic initiation factors (eIFs) are at least as important as the ribosome itself. Some of these factors play different roles throughout the entire process to ensure proper assembly of the preinitiation complex on mRNA, accurate selection of the initiation codon, errorless production of the encoded polypeptide and its proper termination. Perhaps, the most important factor integrating signals from others and coordinating their functions on the ribosome is eIF3. In Saccharomyces cerevisiae, eIF3 is formed by five subunits. All these subunits contain structural motifs responsible for contact with ribosomal proteins and RNAs. In addition to these highly structured parts, the rest of eIF3 is unstructured and very flexible. Therefore, despite the recent progress thanks to the use of a cryo-electron microscopy, a precise structure and position of eIF3 on the 40S ribosomal subunit are still not known. Also, the presence of eIF3 on 80S during early elongation and its role in reinitiation and readthrough are not fully understood. In order to crack mysteries of yeast eIF3, we used x-ray crystallography, chemical cross- linking coupled to mass spectrometry, and various biochemical and genetic assays. We demonstrated that eIF3 is very compactly packed when free in solution. This...
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