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The structure of the mitoribosome from Neurospora crassa with tRNA bound to the E-site
Structural highlights
FunctionRM07_NEUCR Component of the mitochondrial ribosome (mitoribosome), a dedicated translation machinery responsible for the synthesis of mitochondrial genome-encoded proteins, including at least some of the essential transmembrane subunits of the mitochondrial respiratory chain. The mitoribosomes are attached to the mitochondrial inner membrane and translation products are cotranslationally integrated into the membrane.[1] Publication Abstract from PubMedMitoribosomes are specialized protein synthesis machineries in mitochondria. However, how mRNA binds to its dedicated channel, and tRNA moves as the mitoribosomal subunit rotate with respect to each other is not understood. We report models of the translating fungal mitoribosome with mRNA, tRNA and nascent polypeptide, as well as an assembly intermediate. Nicotinamide adenine dinucleotide (NAD) is found in the central protuberance of the large subunit, and the ATPase inhibitory factor 1 (IF(1)) in the small subunit. The models of the active mitoribosome explain how mRNA binds through a dedicated protein platform on the small subunit, tRNA is translocated with the help of the protein mL108, bridging it with L1 stalk on the large subunit, and nascent polypeptide paths through a newly shaped exit tunnel involving a series of structural rearrangements. An assembly intermediate is modeled with the maturation factor Atp25, providing insight into the biogenesis of the mitoribosomal large subunit and translation regulation. Analysis of translating mitoribosome reveals functional characteristics of translation in mitochondria of fungi.,Itoh Y, Naschberger A, Mortezaei N, Herrmann JM, Amunts A Nat Commun. 2020 Oct 14;11(1):5187. doi: 10.1038/s41467-020-18830-w. PMID:33056988[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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