The overall objective of the proposed research is to elucidate the mechanism of protein biosynthesis in subcellular organelles such as chloroplasts and mitochondria. Our immediate goal is to provide a detailed understanding of the mechanism of chloroplast protein biosynthesis in Euglena gracilis and to compare this system to the translational systems of prokaryotes, eukaryotes and of other organelles. Our first objective is to carry out a detailed analysis of the properties of the chloroplast elongation factors EF-Tu and EF-Ts which have recently been purified in our laboratory. We will investigate the binding of aminoacyl-tRNA to EF-Tu and the allosteric interactions between ligand binding sites on this factor. We will then examine the interaction of chloroplast EF-Tu and EF-Ts and will seek to establish the overall mechanism by which the EF-Tu is recycled during the elongation phases of protein synthesis in this organellar system. Our second objective is to complete the purification of the chloroplast factor that binds the initiator tRNA to the small ribosomal subunit during initiation complex formation and to examine the mechanistic details of this process. In addition, we will complete the purification of the chloroplast ribosome dissociation factor, determine its subunit site of action and examine its role in the initiation process. Finally, we will purify the chloroplast mRNA for the large subunit of ribulose 1,5-bisphosphate carboxylase and investigate the factors required for the binding of natural mRNA to chloroplast ribosomes. These factors will be purified and their roles in the initiation process examined in detail. Our long term goal is to develop a defined in vitro system in which to study the regulation of organelle protein biosynthesis, its coordination with cytoplasmic protein synthesis and its integration into the complex metabolism of the cell.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM024963-11
Application #
3272691
Study Section
Physiological Chemistry Study Section (PC)
Project Start
1978-04-01
Project End
1991-03-31
Budget Start
1988-04-01
Budget End
1989-03-31
Support Year
11
Fiscal Year
1988
Total Cost
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Type
Schools of Arts and Sciences
DUNS #
078861598
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Yu, N J; Spremulli, L L (1998) Regulation of the activity of chloroplast translational initiation factor 3 by NH2- and COOH-terminal extensions. J Biol Chem 273:3871-7
Yu, N J; Spremulli, L L (1997) Structural and mechanistic studies on chloroplast translational initiation factor 3 from Euglena gracilis. Biochemistry 36:14827-35
Lin, Q; Yu, N J; Spremulli, L L (1996) Expression and functional analysis of Euglena Gracilis chloroplast initiation factor 3. Plant Mol Biol 32:937-45
Lin, Q; Ma, L; Burkhart, W et al. (1994) Isolation and characterization of cDNA clones for chloroplast translational initiation factor-3 from Euglena gracilis. J Biol Chem 269:9436-44
Betts, L; Spremulli, L L (1994) Analysis of the role of the Shine-Dalgarno sequence and mRNA secondary structure on the efficiency of translational initiation in the Euglena gracilis chloroplast atpH mRNA. J Biol Chem 269:26456-63
Koo, J S; Spremulli, L L (1994) Effect of the secondary structure in the Euglena gracilis chloroplast ribulose-bisphosphate carboxylase/oxygenase messenger RNA on translational initiation. J Biol Chem 269:7501-8
Koo, J S; Spremulli, L L (1994) Analysis of the translational initiation region on the Euglena gracilis chloroplast ribulose-bisphosphate carboxylase/oxygenase (rbcL) messenger RNA. J Biol Chem 269:7494-500
Ma, L; Spremulli, L L (1992) Immunological characterization of the complex forms of chloroplast translational initiation factor 2 from Euglena gracilis. J Biol Chem 267:18356-60
Wang, C C; Spremulli, L L (1991) Chloroplast translational initiation factor 3. Purification and characterization of multiple forms from Euglena gracilis. J Biol Chem 266:17079-83
Lapadat, M A; Deerfield 2nd, D W; Pedersen, L G et al. (1990) Generation of potential structures for the G-domain of chloroplast EF-Tu using comparative molecular modeling. Proteins 8:237-50

Showing the most recent 10 out of 22 publications