title: An efficient and prolonged in vitro translational system from isolated cucumber etioplasts.
abstract: Etioplasts were isolated from dark grown cucumber cotyledons pretreated with kinetin and gibberellic acid. When incubated in a cofactor enriched medium these etioplasts incorporated [35S] methionine into a hot trichloroacetic acid-insoluble fraction; this incorporation was linear for 8 h of incubation and was inhibited by chloramphenicol but not by cycloheximide. Over the same time period, the etioplasts showed continued linear synthesis of the chlorophyll precursors protochlorophyllide, Mg-protoporphyrin and protoporphyrin IX. Analysis of products of in vitro protein synthesis by etioplasts and cotyledons showed the thylakoid membrane polypeptide profiles to be identical. Continued incorporation of [35S] methionine into the large subunit of ribulose bisphosphate carboxylase/oxygenase (RuBisCO) for 8 h has been confirmed further by immunoprecipitation with anti-spinach RuBisCO. This competent in vitro translation system should be useful for future studies of chloroplast protein synthesis and gene expression.
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D002474:Cell-Free System; D002701:Chloramphenicol / Q000494:pharmacology; D002734:Chlorophyll / Q000096:biosynthesis*; D002736:Chloroplasts / Q000378:metabolism*; D003513:Cycloheximide / Q000494:pharmacology; D008565:Membrane Proteins / Q000096:biosynthesis; D008970:Molecular Weight; D010944:Plants; D014176:Protein Biosynthesis; D011758:Pyrroles / Q000096:biosynthesis; D045725:Tetrapyrroles
chemical_list: D000596:Amino Acids; D008565:Membrane Proteins; D011758:Pyrroles; D045725:Tetrapyrroles; D002734:Chlorophyll; D002701:Chloramphenicol; D003513:Cycloheximide