Polypeptide Pattern of Mesophyll and Bundle Sheath Thylakoids of Maize Chloroplasts

The energy converting apparatus of the photosynthesizing oxygenic species organized in several different multisubunit protein complexes is associated with thylakoid membranes. A characteristic feature of C4 plants is the differentiation of the photosynthetic leaf tissues into two distinct cell types, mesophyll (M) and bundle sheath (BS) cells. In this study, polypeptide patterns of mesophyll and bundle sheath thylakoids of maize (Zea mays L.) have been analyzed. The amount of the PSI core apoprotein (68 kDa) was found to be higher in bundle sheath compared with mesophyll thylakoids. α and β subunits (with molecular masses of 55 kDa and 52 kDa) of CF1 domain of the ATPase complex were present in both subcellular fractions. But the amount of α subunit was smaller in the bundle sheath thylakoids. The protein of 45 kDa belonging to the core antenna of PSII was more intensive in mesophyll thylakoids. Polypeptides (with molecular masses in the region of 28-24 kDa) in the composition of the light-harvesting complex II were present in both types of thylakoids. However, in the thylakoids of bundle sheath cells their amounts were reduced.