Primary Citation of Related Structures: 7QP6, 7QP7
PubMed Abstract:
Selection of the translation start codon is a key step during protein synthesis in human cells. We obtained cryo-EM structures of human 48S initiation complexes and characterized the intermediates of codon recognition by kinetic methods using eIF1A as a reporter. Both approaches capture two distinct ribosome populations formed on an mRNA with a cognate AUG codon in the presence of eIF1, eIF1A, eIF2-GTP-Met-tRNAiMet and eIF3. The 'open' 40S subunit conformation differs from the human 48S scanning complex and represents an intermediate preceding the codon recognition step. The 'closed' form is similar to reported structures of complexes from yeast and mammals formed upon codon recognition, except for the orientation of eIF1A, which is unique in our structure. Kinetic experiments show how various initiation factors mediate the population distribution of open and closed conformations until 60S subunit docking. Our results provide insights into the timing and structure of human translation initiation intermediates and suggest the differences in the mechanisms of start codon selection between mammals and yeast.
Organizational Affiliation:
Department of Physical Biochemistry, Max Planck Institute for Multidisciplinary Sciences, Göttingen 37077, Germany.
For questions/corrections to specific PDB entries, including citation updates: email deposit-help@mail.wwpdb.org
Thank you for providing your feedback! Someone will be in touch with you shortly. This window will automatically close in 5 seconds.
Apologies, our feedback server is currently unavailable and we are troubleshooting the issue. In the meantime, please copy and paste the below information into an email addressed to info@rcsb.org