锰、铬和钼重组液及其与部分缺金属原子簇钼铁蛋白重组的比较研究

COMPARATIVE STUDIES ON Mn, Cr AND Mo CONTAINED RECONSTITUENTSOLUTIONSANDPROTEINS RECONSTITUTED WITH PARTIALLY METALLO CLUSTERDEFICIENT MoFe PROTEIN

棕色固氮菌（Ａｚｏｔｏｂａｃｔｅｒｖｉｎｅｌａｎｄｉ）钼铁蛋白经邻菲口罗啉和Ｏ２处理后，缺失一部分ＦｅＭｏｃｏ和Ｐｃｌｕｓｔｅｒ，并失去大部分活性。高柠檬酸铁、Ｎａ２Ｓ和二硫苏糖醇（ＤＴＴ）分别与Ｋ２ＣｒＯ４、ＫＭｎＯ４和Ｎａ２ＭｏＯ４按一定比例混合的具有不同颜色的重组液，均可显著激活失活的钼铁蛋白；然而，除ＤＴＴ可略提高失活蛋白的活性外，其它化合物或缺一、二种化合物的混合液均无激活能力。含９９Ｍｏ重组液与失活蛋白重组后的微分扰动角关联测定显示，该蛋白中的４１％的９９Ｍｏ的状态与克氏肺炎杆菌９９ＭｏＦｅ蛋白中的９９Ｍｏ相似，表明这种激活主要是以金属原子簇含量恢复为基础的。由此可推论出，含Ｍｎ或Ｃｒ的重组液，通过与失活钼铁蛋白重组得到含Ｍｎ或Ｃｒ的固氮酶是可能的。

By treating the reduced MoFe protein from Azotobacter vinelandii with ophenanthroline and O2, an inactive protein partially deficient in both FeMoco and Pcluster could be obtained. The inactive protein could be reactivated by the reconstituent solutions of different colours which were prepared from mixture in different proportions of ferric homocitrate, Na2S and dithiothreitol (DTT) with K2CrO4, KMnO4 and Na2MoO4, respectively, the inactive protein could be somewhat reactivated by DTT but not by the other compounds or their mixtures which were deficient in one or two of the above compounds. 99Mo was found in the reconstituted protein of the inactive MoFe protein with a reconstituent solution containing 99Mo. Its measurement of differential perturbed angular correlation indicated that 41% of 99Mo in the reconstituted protein were in a state similar to that of 99Mo in 99MoFe protein from K. pneumoniae. The results showed that the reactivation of the inactive MoFe protein was mainly based on the restoration of its metallocluster content. It seemed to be reasonable to postulate that Mn or Crcontaining nitrogenase could be obtained likewise by the reconstitution of the inactive protein with the Mn or Crcontaining reconstituent solution .