Translocation of proteins into isolated chloroplasts requires cytosolic factors to obtain import competence

FEBS Letters

Paulsen, Harald¹  Soll, Jürgen¹  Waegemann, Karin¹ 

[1] Botanisches Institut der Universität München, Menzinger Str. 67, D-8000 München 19, FRG

关键词: Protein import;    Chloroplast;    Light-harvesting complex;    Heat-shock protein;    70 kDa;    Soluble factor;    (Pisum sativum L.);    LE;    leaf extract;    hsc 70;    heat-shock protein 70 kDa;    pLHCP;    precursor form of light-harvesting chlorophyll a/b-binding protein;   

DOI  :  10.1016/0014-5793(90)80643-W

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The precursor form of the major-harvesting chlorophyll a/b-binding protein (pLHCP) of chloroplast thylakoids was overproduced in E. coli cells and used to study the influence of soluble factors on post-translational protein import into isolated pea chloroplasts. pLHCP solubilised in 8 M urea was not import-competent. However, if pLHCP was dialysed in the presence of soluble proteins (leaf extract) after urea treatment, import competence was gained. Dialysis of pLHCP in the presence of leaf extract alters its protease sensitivity. Stremai proteins, ovalbumin, trypsin inhibitor or chloroplast lipids could not produce import competence of pLHCP. Two components from leaf extract seem to be necessary, one of which can be mimicked by purified hsc 70, the other one requiring ATP. We conclude that soluble proteins from outside the stromal compartment are necessary for post-translational import of proteins into chloroplasts.

【 授权许可】

Unknown