Abstract: | Crystallization conditions are reported for Streptomyces avidinii streptavidin with and without bound biotin. X-ray examination of the free and bound crystal forms shows the streptavidin-biotin complex crystals to be most suitable for high resolution structure analysis. A complete x-ray data set to 2.6 A resolution was collected for the streptavidin-biotin crystals using a two-dimensional area detector. Reduction and analysis of the x-ray diffraction pattern show that the complex crystallizes in the tetragonal space group I4(1)22 (a = b = 98.4 A, c = 125.8 A), with half of the streptavidin tetramer in the crystallographic asymmetric unit. |