CAJ | 학술논문

在含Mo固氮培养基中不能生长而在无Mo条件下可固氮生长的固氮菌(Azotobacter vinelandii Lipmann)突变种UW3, 能在无Mo而含Cr的无氮培养基中生长.从菌体中分离得到的部分纯固氮酶组分Ⅰ蛋白含有Cr和Fe 原子(Fe/Mo/Cr为11.60∶0.41∶1.00),并能表达相当于棕色固氮菌野生型固氮菌MoFe蛋白对乙炔和质子还原的70%的活性.与从Mn中生长的UW3菌体中所提取纯化的MnFe蛋白不同,这种含铬蛋白与MoFe蛋白(α2β2)一样,是由两种亚基组成的四聚体.初步结果表明,这种含Cr蛋白可能是一种固氮酶组分Ⅰ蛋白.
재함Mo고담배양기중불능생장이재무Mo조건하가고담생장적고담균(Azotobacter vinelandii Lipmann)돌변충UW3, 능재무Mo이함Cr적무담배양기중생장.종균체중분리득도적부분순고담매조분Ⅰ단백함유Cr화Fe 원자(Fe/Mo/Cr위11.60∶0.41∶1.00),병능표체상당우종색고담균야생형고담균MoFe단백대을결화질자환원적70%적활성.여종Mn중생장적UW3균체중소제취순화적MnFe단백불동,저충함락단백여MoFe단백(α2β2)일양,시유량충아기조성적사취체.초보결과표명,저충함Cr단백가능시일충고담매조분Ⅰ단백.
A mutant UW3, which is unable to fix N2 in the presence of Mo (Nif-) but can undergo phenotypic reversal to Nif+ under Mo-deficient conditions, was able to grow in Cr-containing but Mo- and NH3-deficient medium. A partly purified nitrogenase component Ⅰ protein obtained from UW3 grown on the Cr-containing medium was shown to contain Fe and Cr (atom ratio of Fe to Cr and Mo to Cr: 11.60 and 0.41) and to have 70% of the C2H2- and H+-reduction activity of MoFe protein from the wild-type strain of Azotobacter vinelandii Lipmann. The Cr-containing protein was different in subunit composition from that of MnFe protein purified from the mutant strain grown in the presence of Mn, but similar to that of MoFe protein, that is, it was a tetramer composed of two different subunits (α2β2). The preliminary results indicated that the Cr-containing protein might be a nitrogenase component Ⅰ protein.