Component of the mitochondrial large ribosomal subunit (mt-LSU) (PubMed:25278503, PubMed:25838379, PubMed:28892042). The mitochondrial ribosome (mitoribosome) is a large ribonucleoprotein complex responsible for the synthesis of proteins inside mitochondria (PubMed:25278503, PubMed:25838379, PubMed:28892042).