Babiychuk Elena, Müller Frank, Eubel Holger, Braun Hans-Peter, Frentzen Margrit, Kushnir Sergei
Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology, Ghent University, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium.
Plant J. 2003 Mar;33(5):899-909. doi: 10.1046/j.1365-313x.2003.01680.x.
Genetic dissection of the lipid bilayer composition provides essential in vivo evidence for the role of individual lipid species in membrane function. To understand the in vivo role of the anionic phospholipid, phosphatidylglycerol, the loss-of-function mutation was identified and characterized in the Arabidopsis thaliana gene coding for phosphatidylglycerophosphate synthase 1, PGP1. This mutation resulted in pigment-deficient plants of the xantha type in which the biogenesis of thylakoid membranes was severely compromised. The PGP1 gene coded for a precursor polypeptide that was targeted in vivo to both plastids and mitochondria. The activity of the plastidial PGP1 isoform was essential for the biosynthesis of phosphatidylglycerol in chloroplasts, whereas the mitochondrial PGP1 isoform was redundant for the accumulation of phosphatidylglycerol and its derivative cardiolipin in plant mitochondrial membranes. Together with findings in cyanobacteria, these data demonstrated that anionic phospholipids play an important, evolutionarily conserved role in the biogenesis and function of the photosynthetic machinery. In addition, mutant analysis suggested that in higher plants, mitochondria, unlike plastids, could import phosphatidylglycerol from the endoplasmic reticulum.
脂质双层组成的遗传剖析为单个脂质种类在膜功能中的作用提供了重要的体内证据。为了了解阴离子磷脂磷脂酰甘油在体内的作用，在编码磷脂酰甘油磷酸合酶1（PGP1）的拟南芥基因中鉴定并表征了功能丧失突变。该突变导致了黄化型色素缺乏的植物，其中类囊体膜的生物合成受到严重损害。PGP1基因编码一种前体多肽，该多肽在体内靶向质体和线粒体。质体PGP1同工型的活性对于叶绿体中磷脂酰甘油的生物合成至关重要，而线粒体PGP1同工型对于植物线粒体膜中磷脂酰甘油及其衍生物心磷脂的积累是多余的。与蓝细菌中的发现一起，这些数据表明阴离子磷脂在光合机器的生物合成和功能中起重要的、进化上保守的作用。此外，突变分析表明，在高等植物中，线粒体与质体不同，可以从内质网中导入磷脂酰甘油。
