This domain is a protein found in mitochondrial ribosome 54S large sub unit present in species such as Saccharomyces cerevisiae. The domain used to be referred to as MRP25 but is now called mL59 protein. mL59 is known to partially stabilize a change in the rRNA path prior to helix 82-ES1 ultimately leading to the stabilization of the phosphate backbone of the tRNA acceptor stem. It is worth noting that the domain is encoded in the nucleus and imported from the cytoplasm [1].

1: Structure of the yeast mitochondrial large ribosomal subunit. Amunts A, Brown A, Bai XC, Llacer JL, Hussain T, Emsley P, Long F, Murshudov G, Scheres SHW, Ramakrishnan V; Science. 2014;343:1485-1489. PMID:24675956