Under a suitable condition of crystallization, dark brown short rhombohedron crystals could be obtained from nitrogenase MnFe protein purified from a mutant UW 3 of Azotobacter vinelandii Lipmann grown in Mn_containing but Mo_ and NH 3_free medium.

• 从以Mn代钼的固氮培养基中固氮生长的固氮菌 (AzotobactervinelandiiLipmann)突变种UW3 中分离纯化的MnFe蛋白 ,在一定的结晶条件下 ,可从溶液中析出深棕色的短斜四棱柱晶体。