In order to meet the requirement for crystalline growth of O-2-susceptible proteins in space, crystallization conditions on the earth was optimized for the proteins using a simple and suitable device for anaerobic addition of the protein samples. Nitrogenase is susceptible to O-2. Delta nifZ MoFe protein from a nifZ deleted strain and MnFe protein from mutant strain UW3 grown on a medium containing Mn were crystallized at the first time in the world using an anaerobic device equipped with plastic bags or using a small simplified box, as a replacement for the cumbersome dry box. And the proteins could be also crystallized far from laboratory by sitting-drop method using a much lighter device. It was equipped with a smaller plastic food bag and a first-aid bag filled with Ar, as a substitute for the cumbersome dry box and the Ar cylinder, respectively. The results showed that the device could meet the requirement for studies on crystal growth of the above anaerobic proteins in space.
