Primary Citation of Related Structures: 6VLZ, 6VMI
PubMed Abstract:
The mammalian mitochondrial ribosome (mitoribosome) and its associated translational factors have evolved to accommodate greater participation of proteins in mitochondrial translation. Here we present the 2.68-3.96 Å cryo-EM structures of the human 55S mitoribosome in complex with the human mitochondrial elongation factor G1 (EF-G1 mt ) in three distinct conformational states, including an intermediate state and a post-translocational state ...
The mammalian mitochondrial ribosome (mitoribosome) and its associated translational factors have evolved to accommodate greater participation of proteins in mitochondrial translation. Here we present the 2.68-3.96 Å cryo-EM structures of the human 55S mitoribosome in complex with the human mitochondrial elongation factor G1 (EF-G1 mt ) in three distinct conformational states, including an intermediate state and a post-translocational state. These structures reveal the role of several mitochondria-specific (mito-specific) mitoribosomal proteins (MRPs) and a mito-specific segment of EF-G1 mt in mitochondrial tRNA (tRNA mt ) translocation. In particular, the mito-specific C-terminal extension in EF-G1 mt is directly involved in translocation of the acceptor arm of the A-site tRNA mt . In addition to the ratchet-like and independent head-swiveling motions exhibited by the small mitoribosomal subunit, we discover significant conformational changes in MRP mL45 at the nascent polypeptide-exit site within the large mitoribosomal subunit that could be critical for tethering of the elongating mitoribosome onto the inner-mitochondrial membrane.
Organizational Affiliation:
Department of Biomedical Sciences, University at Albany, SUNY, Albany, NY, 12201-0509, USA. rajendra.agrawal@health.ny.gov.
Download Mendeley
