叶绿体atpE基因表达产物的生化特性

在细菌中表达的叶绿体ａｔｐＥ基因产物ε亚基蛋白对不同方式激活的叶绿体ＡＴ－Ｐａｓｅ均有抑制作用，而其抗血清则促进ＡＴ－Ｐａｓｅ活力。Ｅ．ｃｏｌｉ中表达的ε亚基蛋白在光合磷酸化反应中对循环和非循环光合磷酸化都有促进作用，其抗血清对循环光合磷酸化有抑制作用，而对非循环光合磷酸化则起促进作用。

The Properties of Expressed Product of Chloroplast atpE Gene

The maize chloroplast atpE gene,which encodes the E subunit of CF1, thecoupling factor, was over-expressed inE. coli NM522 and then the expressedproduct was purified. The purifiedproduct was found to inhibit the ATPaseactivity of CF1 activated by heat ormethanol (Tables 1 - 3 ). The antiserum raised against the expressed product, stimulated ATPase activity(Table 4 ), and also decreased thequenching of 9-aminoacridine fluorescence (Fig. 1 ). This result can be explained by the antiserum specific binding of the subunit from the CF1,which alleviated the function of E subunit. The expressed product stimulatedcyclic and non--cyclic photophosphorylation and its antiserum stimulated noncyclic photophosphorylation but inhibited cyclic photophosphorylation (Tables5, 6), which can be explained by assuming that the two types of photophosphorylation utilize differently situatedCF1 in thylakoids. Perhaps, ATP formation by non-cyclic photophosphorylation is only synthesized by CF1 of unappressed part of grana thylakoids, butthat by cyclic photophosphorylation issynthesized not only by CFI of un--appressed part of grana thylakoids but alsoCFI of stroma thylakoids.