Mammalian mitochondrial protein synthesis: Mitochondria play a crucial role in the metabolism of mammalian cells. Through the process of oxidative phosphorylation, mitochondria generate about 90 % of the energy used in the cells of higher organisms. Mitochondria contain their own genome and are capable of transcription and translation. The genetic code is altered in this organelle, the transfer RNAs and mRNAs have numerous unusual features and the ribosomes show significant differences from ribosomes of other translational systems.

Our present objective is to combine the techniques of biochemistry and molecular biology to develop an understanding of the mechanism of protein synthesis in animal liver mitochondria. We have purified three factors required for the process of chain elongation and one factor required for the initiation of protein synthesis in animal mitochondria. Large amounts of these proteins are now being prepared by over-expression in E. coli for use in mechanistic studies. Structure/function studies are being carried out in combination site-directed mutagenesis, molecular modeling and biochemical characterization. We are develop a detailed picture of protein-protein and protein-RNA interactions central to mitochondrial translation.

The bulk of the mammalian mitochondrial ribosome consists of proteins. We are using a proteomics approach to identify the proteins in the mammalian mitochondrial ribosome. This approach uses mass spectrometry to obtain peptide sequence information. The human EST database is then searched to provide information on the sequences of the proteins. Using this approach, we hope to develop a complete picture of the spectrum of proteins present in these ribosomes.