| Abstract
| - Bovine mitochondrial ribosomes are presented as a model system for mammalian mitochondrialribosomes. An alternative system for identifying individual bovine mitochondrial ribosomal proteins (MRPs)by RP-HPLC is described. To identify and to characterize individual MRPs proteins were purified frombovine liver, separated by RP-HPLC, and identified by 2D PAGE techniques and immunoblotting.Molecular masses of individual MRPs were determined. Selected proteins were subjected to N-terminalamino acid sequencing. The peptide sequences obtained were used to screen different databases to identifyseveral corresponding MRP sequences from human, mouse, rat, and yeast. Signal sequences formitochondrial import were postulated by comparison of the bovine mature N-termini determined by aminoacid sequencing with the deduced mammalian MRP sequences. Significant sequence similarities of thesenew MRPs to known r-proteins from other sources, e.g., E. coli, were detected only for two of the fourMRP families presented. This finding suggests that mammalian mitochondrial ribosomes contain severalnovel proteins. Amino acid sequence information for all of the bovine MRPs will prove invaluable forassigning functions to their genes, which would otherwise remain unknown.
|
