Chloroplast Biogenesis — Preliminary structural and proteomic study

Abstract

Chloroplast Biogenesis is a multistage process that can be observed on ultrastructural and molecular levels. The correlation between structural and proteomic changes during the chloroplast biogenesis is crucial to elucidate the role of particular proteins in stabilization and transformation of prolamellar body (PLB) and prothylakoids (PT) into characteristic arrangements of thylakoid membranes. The model used in our studies of chloroplast biogenesis represents the differentiation of mature chloroplast from etioplast. This model reflects the initial seedling growth occurring beneath the earth surface. To select the key stages of chloroplast differentiation we performed a quantitative and qualitative analysis of changes in protein composition in the extract from leaves of developing seedlings (Western-blot) simultaneously with studies of the plastid ultrastructure (TEM). We studied and examined the main protein components: Of chloroplast stroma (Rubisco subunits), thylakoid membranes (proteins of photosynthetic complexes) and of prolamellar body characteristic of etioplasts (protochlorophyllide oxidoreductase, POR).