Design and Preparation of the Fragment Proteins of the Flagellar Components Suitable for X-Ray Crystal Structure Analysis.

Terminal disordering in a monomeric state is a common structural property among bacterial flagellar axial proteins. The conformational flexibility of disordered regions of a protein often disturbs its crystallization. Moreover, disordered regions sometimes cause the aggregation problem. Therefore, trimming disordered regions is essential for crystallization of this type of proteins. In this chapter, we describe a simple but powerful method to determine the stable core and metastable fragments of target proteins for crystallization. This method including limited proteolysis in combination with SDS-PAGE and MALDI-TOF mass spectrometry can be applied to almost any proteins containing disordered regions.