Huppe H C, de Lamotte-Guéry F, Buchanan B B
Division of Molecular Plant Biology, University of California, Berkeley 94720, USA.
Planta. 1990;180:341-51.
The components of the ferredoxin-thioredoxin (FT) system of Chlamydomonas reinhardtii have been purified and characterized. The system resembled that of higher plants in consisting of a ferredoxin-thioredoxin reductase (FTR) and two types of thioredoxin, a single f and two m species, m1 and m2. The Chlamydomonas m and f thioredoxins were antigenically similar to their higher-plant counterparts, but not to one another. The m thioredoxins were recognized by antibodies to both higher plant m and bacterial thioredoxins, whereas the thioredoxin f was not. Chlamydomonas thioredoxin f reacted, although weakly, with the antibody to spinach thioredoxin f. The algal thioredoxin f differed from thioredoxins studied previously in behaving as a basic protein on ion-exchange columns. Purification revealed that the algal thioredoxins had molecular masses (Mrs) typical of thioredoxins from other sources, m1 and m2 being 10700 and f 11500. Chlamydomonas FTR had two dissimilar subunits, a feature common to all FTRs studied thus far. One, the 13-kDa ("similar") subunit, resembled its counterpart from other sources in both size and antigenicity. The other, 10-kDa ("variable") subunit was not recognized by antibodies to any FTR tested. When combined with spinach, (Spinacia oleracea L.) thylakoid membranes, the components of the FT system functioned in the light activation of the standard target enzymes from chloroplasts, corn (Zea mays L.) NADP-malate dehydrogenase (EC 1.1.1.82) and spinach fructose 1,6-bisphosphatase (EC 3.1.3.11) as well as the chloroplast-type fructose 1,6-bisphosphatase from Chlamydomonas. Activity was greatest if ferredoxin and other components of the FT system were from Chlamydomonas. The capacity of the Chlamydomonas FT system to activate autologous FBPase indicates that light regulates the photosynthetic carbon metabolism of green algae as in other oxygenic photosynthetic organisms.
莱茵衣藻铁氧化还原蛋白-硫氧还蛋白（FT）系统的组分已被纯化并进行了特性分析。该系统与高等植物的系统相似，由铁氧化还原蛋白-硫氧还蛋白还原酶（FTR）和两种硫氧还蛋白组成，一种是单一的f型，两种是m型，即m1和m2。莱茵衣藻的m型和f型硫氧还蛋白在抗原性上与其高等植物对应物相似，但彼此之间不相似。m型硫氧还蛋白能被针对高等植物m型硫氧还蛋白和细菌硫氧还蛋白的抗体识别，而硫氧还蛋白f则不能。莱茵衣藻硫氧还蛋白f与菠菜硫氧还蛋白f的抗体有反应，尽管反应较弱。藻类硫氧还蛋白f与之前研究的硫氧还蛋白不同，在离子交换柱上表现为碱性蛋白。纯化显示藻类硫氧还蛋白具有其他来源硫氧还蛋白典型的分子量（Mr），m1和m2为10700，f为11500。莱茵衣藻FTR有两个不同的亚基，这是迄今为止所有研究过的FTR的共同特征。一个是13 kDa（“相似”）亚基，其大小和抗原性与其来自其他来源的对应物相似。另一个10 kDa（“可变”）亚基不能被针对任何测试过的FTR的抗体识别。当与菠菜（Spinacia oleracea L.）类囊体膜结合时，FT系统的组分在叶绿体标准靶标酶的光激活中发挥作用，这些酶包括玉米（Zea mays L.）NADP-苹果酸脱氢酶（EC 1.1.1.82）、菠菜果糖1,6-二磷酸酶（EC 3.1.3.11）以及莱茵衣藻的叶绿体型果糖1,6-二磷酸酶。如果铁氧化还原蛋白和FT系统的其他组分来自莱茵衣藻，活性最高。莱茵衣藻FT系统激活自身果糖1,6-二磷酸酶的能力表明，与其他产氧光合生物一样，光调节绿藻的光合碳代谢。
