MRPS21

28S ribosomal protein S21, mitochondrial is a is_associated_with::protein that in humans is encoded by the MRPS21 is_associated_with::gene.

Mammalian mitochondrial ribosomal proteins are encoded by nuclear genes and assist protein synthesis within the mitochondrion. Mitochondrial is_associated_with::ribosomes (mitoribosomes) consist of a small 28S subunit and a large 39S subunit. They have an estimated 75% protein to is_associated_with::rRNA composition compared to is_associated_with::prokaryotic ribosomes, where this ratio is reversed. Another difference between mammalian mitoribosomes and prokaryotic ribosomes is that the latter contain a 5S rRNA. Among different species, the proteins comprising the mitoribosome differ greatly in sequence, and sometimes in biochemical properties, which prevents easy recognition by sequence homology. This gene encodes a 28S subunit protein that belongs to the ribosomal protein S21P family. is_associated_with::Pseudogenes corresponding to this gene are found on chromosomes 1p, 1q, 9p, 10p, 10q, 16q, and 17q. Available sequence data analyses identified splice variants that differ in the 5' UTR; both transcripts encode the same protein.