Koripella, Ravi Kiran and Sharma, Manjuli R. and Bhargava, Kalpana and Datta, Partha P. and Kaushal, Prem S. and Keshavan, Pooja and Spremulli, Linda L. and Banavali, Nilesh K. and Agrawal, Rajendra K. (2020) Structures of the human mitochondrial ribosome bound to EF-G1 reveal distinct features of mitochondrial translation elongation. Nature Communications, 11 (1). ISSN 2041-1723

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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-G1mt) 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-G1mt in mitochondrial tRNA (tRNAmt) translocation. In particular, the mito-specific C-terminal extension in EF-G1mt is directly involved in translocation of the acceptor arm of the A-site tRNAmt. 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.

Item Type:	Article
Subjects:	Biochemical and Biophysical Sciences
Depositing User:	RCB Library
Date Deposited:	04 Jan 2021 09:00
Last Modified:	04 Jan 2021 09:00
URI:	http://rcb.sciencecentral.in/id/eprint/521

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