Exclusion of ribulose-1,5-bisphosphate carboxylase/oxygenase from chloroplasts by specific bodies in naturally senescing leaves of wheat
Exclusion of ribulose-1,5-bisphosphate carboxylase/oxygenase from chloroplasts by specific bodies in naturally senescing leaves of wheat
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DOI：
10.1093/pcp/pcg118
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发表时间：
2003-09-01
影响因子：
4.9
通讯作者：
Mae, T
中科院分区：
文献类型：
--
作者：
Chiba, A;Ishida, H;Mae, T
免疫细胞化学电镜观察表明，核酮糖-1,5-二磷酸羧化酶/加氧酶（Rubisco，EC 4.1.1.39）和/或其降解产物位于自然衰老的小麦（Triticum aestivum L.）叶片中直径为0.4-1.2μm的小球体中。这些含有 Rubisco 的小体 (RCB) 存在于细胞质和液泡中。 RCB 含有另一种基质蛋白，即叶绿体谷氨酰胺合成酶，但不含类囊体蛋白。超微结构分析表明，RCB 具有双层膜，似乎源自叶绿体包膜，并且 RCB 进一步被细胞质中的其他膜结构包围。当Rubisco的量在叶片衰老早期开始减少时，RCBs的出现最为显着。这些结果表明，RCB 可能参与了叶片衰老过程中叶绿体外 Rubisco 的降解过程。
Immunocytochemical electron-microscopic observation indicated that ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco, EC 4.1.1.39) and/or its degradation products are localized in small spherical bodies having a diameter of 0.4-1.2 mum in naturally senescing leaves of wheat (Triticum aestivum L.). These Rubisco-containing bodies (RCBs) were found in the cytoplasm and in the vacuole. RCBs contained another stromal protein, chloroplastic glutamine synthetase, but not thylakoid proteins. Ultrastructural analysis suggested that RCBs had double membranes, which seemed to be derived from the chloroplast envelope, and that RCBs were further surrounded by the other membrane structures in the cytoplasm. The appearance of RCBs was the most remarkable when the amount of Rubisco started to decrease at the early phase of leaf senescence. These results suggest that RCBs might be involved in the degradation process of Rubisco outside of chloroplasts during leaf senescence.