Protein prenylation in spinach chloroplasts.
Protein prenylation in plants was studied by in vivo metabolic (3)H-mevalonate labeling in combination with a range of protein synthesis inhibitors. In spinach cotyledons, this posttranslational protein modification was found to be divided into two categories, one representing the conventional prenylation involving farnesyl and geranylgeranyl groups bound to cysteine residues via thioether linkages. This category revealed a similar pattern of prenylated proteins to that observed in mammalian cells and depends on nuclear gene expression. The other category was shown to represent a type of prenylation confined to chloroplasts. It depends on plastid gene expression and does not involve a thioether bond. The modifying isoprenoid could be released from the chloroplastic polypeptides by alkaline treatment and was identified as phytol upon GC-MS analysis. The phytol could readily be derived from all-trans-[(3)H]farnesol, which, like all-trans-[(3)H]geranylgeraniol, was taken up by the cotyledons, resulting in incorporation of radiolabel into proteins.
Parmryd
I
I
Department of Biochemistry, Arrhenius Laboratories for Natural Sciences, Stockholm University, S-106 91 Stockholm, Sweden. ingela@biokemi.su.se
Andersson
B
B
Dallner
G
G
D000818:Animals; D002458:Cell Fractionation; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism*; D018548:Cotyledon / Q000378:metabolism; D004224:Diterpenes / Q000378:metabolism; D005204:Farnesol / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D008322:Mammals; D008798:Mevalonic Acid / Q000378:metabolism; D010940:Plant Proteins / Q000302:isolation & purification / Q000378:metabolism*; D017368:Protein Prenylation; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D018724:Spinacia oleracea / Q000378:metabolism; D014316:Tritium
D004224:Diterpenes; D010940:Plant Proteins; D011500:Protein Synthesis Inhibitors; D014316:Tritium; D005204:Farnesol; C017338:geranylgeraniol; D008798:Mevalonic Acid