Steve Ealick's Research Group

Abstract:

Sukumar N, Mathews FS, Gordon MM, Ealick SE, and Alpers DH. Postcrystallization Analysis of the Irreproducibility of the Human Intrinsic Factor-Cobalamin Complex Crystals. Cryst. Growth Des. 9:348-351 (2009).

Approx. 15% (wt./wt.) of human intrinsic factor (IF) is comprised of carbohydrate side chains, making crystn. problematic. In addn., IF is sensitive to proteolysis. To understand the role of these factors in crystn., the authors carried out dynamic light scattering studies and assessed their correlation with crystn. The packing of the IF-cobalamin complex and the known properties of the protein in soln. were also analyzed to explore the irreproducibility of the IF-cobalamin complex crystals and the difficulty in obtaining apo-IF crystals suitable for crystallog. anal. The results indicate that although glycosylation may in general be inhibitory for crystn., time-dependent proteolysis appears to play a much more important role in the process of crystn. of IF. Thus, the presence of cobalamin and of domain fragments that can form incomplete dimers lacking one of two beta -domains appears to promote the crystn. of IF.