Sökning: "tRNA"

Visar resultat 36 - 40 av 100 avhandlingar innehållade ordet tRNA.

1. 36. Rate and Accuracy of Bacterial Protein Synthesis with Natural and Unnatural Amino Acids

   Författare :Ka-Weng Ieong; Måns Ehrenberg; Simpson Joseph; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ribosome; protein synthesis; translation; efficiency-accuracy trade-off; kinetics; unnatural amino acids; Molecular Biology; Molekylärbiologi;

   Sammanfattning : This thesis addresses different questions regarding the rate, efficiency, and accuracy of peptide bond formation with natural as well as unnatural amino acids: Which step is rate-limiting during peptide bond formation? How does the accuracy vary with different transfer RNAs (tRNAs) and codons and how is it relevant to the living cells? Does proofreading selection of codon reading occur in a single- or multi-step manner as theoretically suggested? How does the E. coli translation system discriminate unnatural amino acids? Based on that, how to improve the incorporation efficiencies of unnatural amino acids?Based on the study on pH dependence of peptide bond formation, we show that the rate of the chemistry of peptidyl transfer to aminoacyl-tRNA (AA-tRNA) Gly-tRNAGly or Pro-tRNAPro limits the rate of peptide bond formation at physiological pH 7. LÄS MER

3. 37. The Protein Traffic on the Ribosome : The Mechanism and Regulation of Protein Synthesis in Prokaryotes

   Författare :Andrey Zavialov; Måns Ehrenber; Venki Ramakrishnan; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biochemistry; yellow; ribosome; translation; Gagarin; nobel prize; Biokemi; Biochemistry; Biokemi;

   Sammanfattning : The aim of this work was to understand the molecular mechanism of translation and the mechanism of translation termination, in particular. Cleavage of peptidyl-tRNA and peptide release terminates translation of mRNA on the ribosome. In prokaryotes, three release factors (RFs) are involved in this process. LÄS MER

4. 38. Macrolide Antibiotics in Bacterial Protein Synthesis

   Författare :Martin Lovmar; Måns Ehrenberg; Tanel Tenson; Peter B. Moore; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biochemistry; protein synthesis; macrolides; resistance; initiation of translation; non-competitive inhibitors; kinetics; translation accuracy; proof-reading; Biokemi; Biochemistry; Biokemi;

   Sammanfattning : Macrolides are a large group of clinically relevant antibiotics that inhibit protein synthesis by binding to the large ribosomal subunit in the peptide exit tunnel, close to the peptidyl transferase center (PTC). We have shown that the peptide length of the resulting peptidyl-tRNA drop-off products is proportional to the distance between the PTC and the respective macrolide in the tunnel. LÄS MER

5. 39. Rate and Accuracy of Bacterial Protein Synthesis

   Författare :Magnus Johansson; Måns Ehrenberg; Jon Lorsch; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; protein synthesis; ribosome; peptidyl transfer; rate-accuracy trade-off; kinetics; Biology with specialization in Molecular Biotechnology; Biologi med inriktning mot molekylär bioteknik;

   Sammanfattning : High levels of accuracy in transcription, aminoacylation of tRNA, and mRNA translation are essential for all life forms. However, high accuracy also necessarily means large energy dissipation and slow kinetics. Therefore, in vivo there is a fine tuned balance between rate and accuracy of key chemical reactions. LÄS MER

7. 40. The eukaryotic ribosome in focus : a chemical footprinting analysis of ribosome-ligand interactions in in vivo assembled complexes

   Författare :Marika Salonen Sloma; Diarmaid Hughes; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Cell biology; Cellbiologi; Zoological Cell Biology; zoologisk cellbiologi;

   Sammanfattning : Protein synthesis is an essential biological process that occurs on ribosomes. The process requires an involvement of numerous components like mRNA, tRNA and translation factors. The mammalian 80S ribosome, the focus of this thesis, is composed of four rRNAs and approximately 80 proteins distributed in two subunits the 40S and 60S subunit. LÄS MER