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

(1)以百合(Lilium Long Giflorum)代替水稻(Oryza Sativa)作为主要的实验植物。(2)从百合和水稻的线粒体中分离纯化了F_1-ATPase。两种酶均由5种亚基组成。用兔制备抗百合F1-ATPase抗体。百合的亚线粒体颗粒(SMP)中也纯化了F_0F_1-ATPase，但F_0F_1-ATPase的亚基组成尚不清楚。(3)提纯的F_0F_1-ATPase具有组织特异性。花粉F_0F_1-ATPase活性在供试组织中最高，鳞茎最低。(4)从不同组织分离的F_0F_1-ATPase中，F_0部分与F_1部分的交叉重组实验表明，F_0部分的不同性质可能是导致组织特异性活性的原因。此外，不同组织中F_0F_1-ATPase的F_0部分所在的膜脂组成也不同。(5)从SMP中分离纯化了一种F_0F_1-ATPase抑制蛋白，其分子质量为16kd。这种抑制蛋白在鳞茎中的含量似乎比在花粉中的含量要高。本研究中发现的抑制物对进一步研究F_0F_1-ATPase的分子形态具有重要意义。(6)我们尝试利用培养的水稻细胞来评价矿质元素对线粒体F_0F_1-ATPase的作用。缺锌缺锰导致SMP F_0F_1-ATPase活性严重降低，缺锌缺锰降低F_0F_1-ATPase活性的机制尚不清楚。

(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.