锰对部分缺失金属原子簇的固氮酶钼铁蛋白的重组作用  

THE EFFECT OF MANGANESE ON THE RECONSTITUTION OF PARTIAL METALLOCLUSTER DEFICIENT NITRO GENASE MOLYBDENUM IRON PROTEIN

作　　者：黄巨富[1] 汪志平[1] 骆爱玲[1] 钟泽璞[1] 李佳格 

机构地区：[1]中国科学院植物研究所,北京100044

出　　处：《Acta Botanica Sinica》1994年第6期411-417,共7页Acta Botanica Sinica（植物学报：英文版）

基　　金：国家基础性重大关键项目;国家自然科学基金

摘　　要：棕色固氮菌（Ａｚｏｔｏｂａｃｔｅｒ ｖｉｎｅｌａｎｄｉｉ）固氮酶钼铁蛋白经邻菲口罗啉和Ｏ２ 处理后，变为部分缺失Ｐ－ｃｌｕｓｔｅｒ和ＦｅＭｏｃｏ 的失活蛋白，经与由ＫＭｎＯ４、高柠檬酸铁、Ｎａ２Ｓ和二硫苏糖醇组成的重组液保温后，重组蛋白的吸收光谱和对Ｃ２Ｈ２、Ｈ＋ 和Ｎ２ 的还原活性都恢复至与还原钼铁蛋白相似的状态，而它的α－螺旋度和在３８０—５５０ ｎｍ 、６２０—６７０ ｎｍ 的ＣＤ谱虽有明显的恢复，但仍与还原钼铁蛋白有所不同。表明：（１）重组蛋白液既含有在缺失金属原子簇的ＭｏＦｅ蛋白与含Ｍｎ 重组液重组过程中可能组装的ＭｎＦｅ 蛋白，又含有在邻菲口罗啉和Ｏ２ 处理后金属原子簇仍旧完整的ＭｏＦｅ蛋白；（２）ＭｎＦｅ蛋白和ＭｏＦｅ蛋白在固氮能力上可能是相似的。By treating the reduced MoFe protein of nitrogenase from Azotobacter vinelandii with O phenanthroline (O phen) and O 2, inactive MoFe protein which was partialy deficient in both P cluster and FeMoco could be obtained. After incubating the inactive protein with a reconstituent solution containing KMnO 4, ferric homocitrate, Na 2S and dithiothreitol, a reconstituted protein could be obtained. The absorption spectrum and C 2H 2,H + and N 2 reduction activity of the reconstituted protein could be well restored to the state of the reduced MoFe protein. However, the α helix and CD spectrum at 380—550 nm and at 620—670 nm of the reconstituted protein were somewhat different from those of the reduced MoFe protein. The results showed that:(1) the reconstituted protein was composed of the assembled protein which might be a MnFe protein due to the reconstitution of the metallocluster deficient MoFe protein with Mn containing solution and MoFe protein in which metalloclusters were still intact after the treatment with O phen and O 2; (2) It might be possible that the MnFe protein and MoFe protein were similar in the ability of nitrogen fixation, but were somewhat different in the structure from each other.

关 键 词：锰铁蛋白 钼铁蛋白 固氮酶 固氮菌 

分 类 号：Q945.13[生物学—植物学]