Showing papers by "Harry F. Noller published in 1998"
TL;DR: The interaction of translational elongation factor EF-G with the ribosome in the posttranslocational state has been mapped by directed hydroxyl radical probing and the proximities of different domains ofEF-G to well-characterized elements of rRNA have additional implications for the mechanism of protein synthesis.
228 citations
TL;DR: The ability to move mRNA and tRNA is an inherent of aminoacyl-tRNA, a spontaneous reaction catalyzed property of the ribosome; the factors serve to increase by peptidyl transferase, the speed and accuracy of elongation in a GTP-depen results in peptide bond formation and transfer of the dent manner.
195 citations
TL;DR: A structural feature of the ribosome between the A and P sites, interferes with movement of tRNA analogs that exceed the normal dimensions of the coaxial tRNA anticodon‐D arm, suggesting that other elements of P‐site tRNA structure are required for translocation.
Abstract: The authors apologise for an error in Figure 1C. The arrows pointing to the toeprint positions were off by one position. The corrected figure below shows the correct toeprint positions.
Figure 1.
Construction …
113 citations
TL;DR: This result places the conserved 2555 loop of 23S rRNA at the peptidyl transferase A site and suggests that peptide bond formation can occur uncoupled from movement of the A-site tRNA.
Abstract: In the ribosome, the aminoacyl-transfer RNA (tRNA) analog 4-thio-dT-p-C-p-puromycin crosslinks photochemically with G2553 of 23S ribosomal RNA (rRNA). This covalently linked substrate reacts with a peptidyl-tRNA analog to form a peptide bond in a peptidyl transferase-catalyzed reaction. This result places the conserved 2555 loop of 23S rRNA at the peptidyl transferase A site and suggests that peptide bond formation can occur uncoupled from movement of the A-site tRNA. Crosslink formation depends on occupancy of the P site by a tRNA carrying an intact CCA acceptor end, indicating that peptidyl-tRNA, directly or indirectly, helps to create the peptidyl transferase A site.
82 citations
TL;DR: Results are consistent with previous footprinting data that localized S20 near these 16S rRNA elements, providing evidence that S20, like S17, is located near the bottom of the 30S subunit.
Abstract: The 16S ribosomal RNA neighborhood of ribosomal protein S20 has been mapped, in both 30S subunits and 70S ribosomes, using directed hydroxyl radical probing. Cysteine residues were introduced at amino acid positions 14, 23, 49, and 57 of S20, and used for tethering 1-(p-bromoacetamidobenzyl)-Fe(II)-EDTA. In vitro reconstitution using Fe(II)-derivatized S20, together with the remaining small subunit ribosomal proteins and 16S ribosomal RNA (rRNA), yielded functional 30S subunits. Both 30S subunits and 70S ribosomes containing Fe(II)-S20 were purified and hydroxyl radicals were generated from the tethered Fe(II). Hydroxyl radical cleavage of the 16S rRNA backbone was monitored by primer extension. Different cleavage patterns in 16S rRNA were observed from Fe(II) tethered to each of the four positions, and these patterns were not significantly different in 30S and 70S ribosomes. Cleavage sites were mapped to positions 160-200, 320, and 340-350 in the 5' domain, and to positions 1427-1430 and 1439-1458 in the distal end of the penultimate stem of 16S rRNA, placing these regions near each other in three dimensions. These results are consistent with previous footprinting data that localized S20 near these 16S rRNA elements, providing evidence that S20, like S17, is located near the bottom of the 30S subunit.
27 citations
TL;DR: A strong footprint for L15 is identified in the region spanning nucleotides 572-654 in domain II of 23 S rRNA, consistent with its central role in the latter stages of 50 S subunit assembly.
18 citations