This family consists of the yeast mitochondrial ribosomal proteins VAR1. Mitochondria possess their own ribosomes responsible for the synthesis of a small number of proteins encoded by the mitochondrial genome. In yeast the two ribosomal RNAs and a single ribosomal protein, VAR1, are products of mitochondrial genes, and the remaining approximately 80 ribosomal proteins are encoded in the nucleus [1]. VAR1 along with 15S rRNA are necessary for the formation of mature 37S subunits [2].
Ribosomes are the particles that catalyse mRNA-directed protein synthesis in all organisms. The codons of the mRNA are exposed on the ribosome to allow tRNA binding. This leads to the incorporation of amino acids into the growing polypeptide chain in accordance with the genetic information. Incoming amino acid monomers enter the ribosomal A site in the form of aminoacyl-tRNAs complexed with elongation factor Tu (EF-Tu) and GTP. The growing polypeptide chain, situated in the P site as peptidyl-tRNA, is then transferred to aminoacyl-tRNA and the new peptidyl-tRNA, extended by one residue, is translocated to the P site with the aid the elongation factor G (EF-G) and GTP as the deacylated tRNA is released from the ribosome through one or more exit sites [PUBMED:11297922, PUBMED:11290319]. About 2/3 of the mass of the ribosome consists of RNA and 1/3 of protein. The proteins are named in accordance with the subunit of the ribosome which they belong to - the small (S1 to S31) and the large (L1 to L44). Usually they decorate the rRNA cores of the subunits.
Mason TL, Pan C, Sanchirico ME, Sirum-Connolly K; , Experientia 1996;52:1148-1157.: Molecular genetics of the peptidyl transferase center and the unusual Var1 protein in yeast mitochondrial ribosomes. PUBMED:8988258 EPMC:8988258 .
Davis SC, Ellis SR; , Mol Gen Genet 1995;247:379-386.: Incorporation of the yeast mitochondrial ribosomal protein Mrp2 into ribosomal subunits requires the mitochondrially encoded Var1 protein. PUBMED:7770043 EPMC:7770043.
