Phosphopantethenylated Precursor Acyl Carrier Protein Is Imported into Spinach (Spinacia oleracea) Chloroplasts.
AUTOR(ES)
Savage, L. J.
RESUMO
Acyl carrier protein (ACP) is an essential cofactor of fatty acid synthase. In plants, ACP is synthesized in the cytosol as a larger precursor protein and then is imported into the plastid where it is processed to a smaller mature form. The active form of ACP uses a covalently linked 4[prime]-phosphopantetheine prosthetic group derived from coenzyme A to covalently bind the acyl intermediates during fatty acid synthesis. The prosthetic group is added to ACP by holoACP synthase. This enzyme activity is associated with both the plastidial subcellular fraction and the soluble, or cytoplasmic, fraction. To gain further insight into potential in vivo pathways for the synthesis and maturation of ACP, in this study we examined whether precursor holoACP can be imported by isolated spinach (Spinacia oleracea) chloroplasts. Precursor holoACP containing a [35S]phosphopantetheine prosthetic group was prepared, and the radiolabel was used to demonstrate import of the phosphopantethenylated protein into isolated chloroplasts. In addition, timed chloroplast import assays indicated that in vitro import of the phosphopantethenylated protein is at least as efficient as import of the precursor apoprotein. Evidence was also obtained for a low level turnover of the prosthetic group among endogenous plastidial ACPs when coenzyme A was supplied exogenously.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=160697Documentos Relacionados
- 3-Ketoacyl-acyl carrier protein synthase III from spinach (Spinacia oleracea) is not similar to other condensing enzymes of fatty acid synthase.
- Effects of Anaerobiosis on Chlorophyll Fluorescence Yield in Spinach (Spinacia oleracea) Leaf Discs.
- Identification of a Protein That Inhibits the Phosphorylated Form of Nitrate Reductase from Spinach (Spinacia oleracea) Leaves.
- Goitrogenic/antithyroidal potential of moringa leaves (Moringa oleifera) and spinach (Spinacia oleracea) of Indian origin on thyroid status in male albino rats
- Subcellular localization of acyl carrier protein in leaf protoplasts of Spinacia oleracea.