Chloroplast import of four carotenoid biosynthetic enzymes in vitro reveals differential fates prior to membrane binding and oligomeric assembly
| Autor: | Johannes von Lintig, Michael Bonk, Elias Hobeika, Salim Al-Babili, Michael Schledz, Benedikt Hoffmann, Hans Kleinig, Peter Beyer |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Phytoene desaturase
Chloroplasts Molecular Sequence Data Biochemistry Adenosine Triphosphate Stroma Transferases Farnesyltranstransferase Cloning Molecular Intramolecular Lyases Isomerases chemistry.chemical_classification Phytoene synthase Alkyl and Aryl Transferases biology Peas Biological Transport Chaperonin 60 Carotenoids Chloroplast Cold Temperature Molecular Weight Chloroplast stroma Enzyme chemistry Thylakoid Geranylgeranyl-Diphosphate Geranylgeranyltransferase Liposomes biology.protein Oxidoreductases |
| Zdroj: | European journal of biochemistry. 247(3) |
| ISSN: | 0014-2956 |
| Popis: | The precursor proteins of the carotenogenic enzymes geranylgeranyl diphosphate synthase, phytoene synthase, phytoene desaturase and lycopene cyclase were imported into isolated pea chloroplasts. Geranylgeranyl diphosphate synthase remained soluble in the stroma in a free form and phytoene synthase associated to thylakoid membranes upon import, both as expected. Surprisingly, phytoene desaturase and lycopene cyclase, which strongly depend on membrane association for enzymatic activity, also remained soluble in the chloroplast stroma. The soluble forms of these enzymes were, however, still competent for membrane-association, e.g. with protein-free liposomal membranes. Indeed the soluble forms of phytoene synthase, phytoene desaturase and lycopene cyclase occurred as ATP- and cold-sensitive high-molecular-mass complexes. Gel-filtration experiments and blue native-PAGE plus autoradiography and western blot analysis indicated a participation of the chloroplast 60-kDa chaperonin (Cpn60) in the soluble high-molecular-mass complexes of imported carotenogenic enzymes. Finally, it was inferred that a membrane-bound regulatory factor plays a decisive role in membrane-binding. |
| Databáze: | OpenAIRE |
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