Large mitochondrial ribosomal subunit (mt-LSU)

The **large mitochondrial ribosomal subunit** (mt-LSU) is the 39S component of the mammalian mitochondrial ribosome (mitoribosome), an essential machine for synthesizing 13 mitochondrial-encoded proteins critical for oxidative phosphorylation[5][1]. This ribonucleoprotein complex is highly divergent from bacterial and cytoplasmic ribosomes, featuring a drastically reduced rRNA core and an expanded set of proteins, many unique to mitochondria[2][1][7]. The mt-LSU includes the peptidyl transferase center, the nascent polypeptide exit tunnel, and a specialized central protuberance incorporating mitochondrial tRNA^Val^ as a structural component instead of the typical 5S rRNA[1][5][7]. It initiates and catalyzes peptide bond formation during translation of mtDNA-encoded membrane proteins, integrating them into the inner mitochondrial membrane to support electron transport and ATP generation[3][5]. Mutations in mt-LSU components are linked to a variety of human mitochondrial disorders, and many antibiotics can inadvertently inhibit this subunit, resulting in therapeutic challenges and side effects[1][4][9].

Other names

Mitochondrial large ribosomal subunit39S ribosomal subunit (in mammals)Mammalian mitoribosome large subunit

Inhibition of mitochondrial translation through binding to mitochondrial ribosomal subunits, interfering with the peptidyl transferase center or tRNA sites