Molecular Analysis of Rice Mitochondrial F_0F_1-ATPase and Effect of Mineral Element Deficienct on the Enzyme

(1)以百合（Lilium longiflorum）代替水稻（Oryza sativa）作为主要试验植物。(2)从百合和水稻线粒体中纯化了F_1-ATPase。两种酶均由5种亚基组成。用家兔制备了抗百合F_1-ATPase的抗体。从百合的亚线粒体颗粒（SMP）中也分离纯化了F_0F_1-ATPase，但其亚基组成尚不清楚。(3)纯化的F_0F_1-ATPase在SMP上具有组织特异性活性。花粉F_0F_1-ATPase活性最高，鳞茎最低。(4)从F_0和F_1部分的交叉重组实验中可以看出，不同组织中F_0、F_1-ATP酶的F_0部分性质不同，可能导致了F_0、F_1-ATP酶的组织特异性。此外，F_0F_1-ATPase的F_0部分所处的膜脂组成在不同组织间也存在差异。(5)从SMP中分离纯化了一种F_0F_1-ATPase抑制蛋白，其分子量为16 kd。抑制蛋白出现在鳞茎中的量大于花粉。本研究中发现的F_0F_1-ATP酶抑制剂对进一步研究F_0F_1-ATP酶的分子形式具有重要意义。(6)本研究以水稻细胞为材料，探讨了矿质元素对线粒体F_0F_1-ATPase的影响。缺锌、缺锰导致SMP上F_0F_1-ATPase活性显著降低，其机制尚待进一步研究。

(1) Lily plant (Lilium longiflorum) was used as a major experimental plant instead of rice (Oryza sativa).(2) F_1-ATPase was purified from mitochondria of lily and rice plants to a homogeneity. Both enzymes consisted of 5 kinds of subunits. Antibody against lily F_1-ATPase was prepared using rabbit. F_0F_1-ATPase was also purified from submitochondrial particles (SMP) of lily plants ; however, subunit constitution of the lily F_0F_1-ATPase remains to be solved.(3) We found a tissue-specific activity of F_0F_1-ATPase on SMP when purified F_0F_1-ATPase. Pollen F_0F_1-ATPase showed the highest activity among the tissues tested and bulbs the lowest one.(4) Different properties of F_0-portions in F_0F_1-ATPases isolated from different tissues may cause the tissue-specific activities, judged from the experiments of cross-reconstitution of F_0- and F_1-portions. In addition, lipid composition of the membrane where F_0-portion of F_0F_1-ATPase locates was also different among the different tissues tested.(5) We isolated and purified an F_0F_1-ATPase inhibitor protein from SMP.The molecular size of the inhibitor was 16 kd. The inhibitor protein appeared to be present in bulbs in a larger amount than in pollens. The inhibitor we found in this study will be crucial to further investigate the molecular form of F_0F_1-ATPase.(6) We have attempted to evaluate the role of mineral elements for mitochondrial F_0F_1-ATPase using cultured rice cells. Zinc- and manganese-deficiency caused a severe reduction of F_0F_1-ATPase activity on SMP.Mechanism of reduction of F_0F_1-ATPase activity by zinc and manganese starvation remains to be solved.